Determining information about devices in a building using different sets of features

ABSTRACT

Electrical usage of devices in a building may be monitored to provide information about the operation of the devices to a user. The information communicated to a user may include historical information and real-time information. In determining the real-time information, it may be desired to provide the information quickly and use a smaller set of features that are available more quickly. In determining the historical information, it may be desired to provide more accurate information and use a larger set of features. A device may compute real-time information and historical information using different sets of features.

BACKGROUND

Reducing electricity usage provides the benefits, among others, ofsaving money by lowering payments to electric companies and alsoprotecting the environment by reducing the amount of resources needed togenerate the electricity. Electricity users, such as consumers,businesses, and other entities, may thus desire to reduce theirelectrical usage to achieve these benefits. Users may be able to moreeffectively reduce their electricity usage if they have informationabout what devices (e.g., refrigerator, oven, dishwasher, furnace, andlight bulbs) in their homes and buildings are using the most electricityand what actions are available to reduce electricity usage.

Electricity monitors for individual devices are available for measuringthe electricity usage of a single device. For example, a device can beplugged into an electricity monitor, and the monitor can in turn beplugged into a wall outlet. These monitors can provide information aboutelectricity usage for the one device they are attached to, but it maynot be practical to monitor all or even many devices in a house orbuilding with these monitors, because it would require a large number ofdevices that can be expensive and also require significant manual effortto install.

Instead of an electricity monitor for a single device, an electricitymonitor can be installed at an electrical panel to obtain informationabout electricity used by many devices simultaneously. An electricitymonitor on an electrical panel is more convenient because a singlemonitor can provide aggregate usage information about many devices. Itis more difficult, however, to extract more specific information aboutusage of electricity by a single device, since the monitor typicallymeasures one signal (or several signals for different zones of the houseor building) that reflects the collective operation of many devices,which may overlap in complex ways. The process of obtaining informationabout the electricity usage of a single device from an electrical signalcorresponding to usage by many devices may be referred to asdisaggregation.

To provide the greatest benefits to end users, a need exists for moreaccurate disaggregation techniques, so that end users receive accurateinformation about the electrical usage of individual devices. A needalso exists for faster disaggregation techniques, so that end users andothers can receive information about electrical usage in real time.

BRIEF DESCRIPTION OF THE FIGURES

The invention and the following detailed description of certainembodiments thereof may be understood by reference to the followingfigures:

FIG. 1 illustrates one example of a system for performing disaggregationof electrical signals and providing information a user.

FIG. 2 illustrates components of one implementation of a power monitor.

FIG. 3 illustrates a timeline of computing features for an electricalevent and a data structure for storing the features.

FIG. 4 illustrates an example of a device model that may be used with apower monitor.

FIG. 5 illustrates an example of a search graph that may be used fordetermining information about devices.

FIG. 6 illustrates an example of an architecture for providinginformation about devices from a power monitor to a user.

FIGS. 7A-7G illustrate example displays for providing information to auser about devices in the home.

FIG. 8 illustrates components of one implementation of a server fordiscovering devices in a home and updating models for devices in a home.

FIG. 9 illustrates an electrical signal with electrical events from twodevices.

FIG. 10 illustrates an example of a discovery graph that may be used fordiscovering new devices.

FIG. 11 is a flowchart showing an example implementation for providinghistorical and real-time information about devices.

FIG. 12 is a flowchart showing an example implementation of presentinghistorical and real-time information about devices to a user.

FIG. 13 is a flowchart showing an example implementation of a networkarchitecture for providing real-time information about devices.

FIG. 14 is a flowchart showing an example implementation of determininginformation about device events.

FIG. 15 is a flowchart showing an example implementation of discoveringdevices in a building.

FIG. 16 is a flowchart showing an example implementation of determininghouse-specific models for determining information about devices.

FIG. 17 is a flowchart showing an example implementation of determininginformation about devices using a graph, such as a search graph.

DETAILED DESCRIPTION

Described herein are techniques for disaggregating electrical signalscontaining information about multiple devices to obtain informationabout electrical usage by individual devices, techniques for effectivelypresenting this information to end users, and techniques for allowingthe end users to take actions, such as to conserve energy.

FIG. 1 illustrates one example of a system for performing disaggregationof electrical signals and providing information to a user relating todevices that are consuming the electrical signals. FIG. 1 and otherfigures will be described with reference to electricity usage in a hometo simplify the explanation of the techniques described herein, but thetechniques described herein are equally applicable to any environmentwhere electricity is used, including but not limited to businesses andcommercial buildings, government buildings, and other venues. Referencesto homes throughout should be understood to encompass such other venues.

In FIG. 1, electrical panel 110 may be an electrical panel that istypical in many homes. Electrical panel 110 receives electricity from anelectric utility and processes the electricity so that it may be used bydevices in the home. Typically, the electricity is alternating current(AC). For example, electrical panel 110 may implement split-phaseelectric power, where a 240 volt AC electrical signal is converted witha split-phase transformer to a three-wire distribution with a singleground and two mains (or legs) that each provide 120 volts. Some devicesin the house may use one of the two mains to obtain 120 volts; otherdevices in the house may use the other main to obtain 120 volts; and yetother devices may use both mains simultaneously to obtain 240 volts.Other voltage standards, such as for other countries or continents, areintended to be encompassed herein as would be understood by one ofordinary skill in the art.

Any type of electrical panel may be used, and the techniques describedherein are not limited to a split phase electrical panel. For example,electrical panel 110 may be single phase, two phase, or three phase. Thetechniques are also not limited to the number of mains provided byelectrical panel 110. In the discussion below, electrical panel 110 willbe described as having two mains, but any number of mains may be used,including just a single main.

FIG. 1 shows devices 100 that are consuming electricity provided byelectrical panel 110. For example, one device may be a televisionreceiving electricity from a first main, another device may be a washingmachine receiving electricity using two mains, and another device may bea light bulb receiving electricity from a second main.

FIG. 1 shows power monitor 120 that may perform disaggregation usinginformation about one or more electrical signals provided by electricalpanel 110. For example, power monitor 120 may determine voltage and/orcurrent levels for electrical signals output by electrical panel 110(e.g., one or more mains). The values may be determined using anyavailable sensors, and the techniques are not limited to any particularsensors or any particular types of values that may be obtained fromsensors.

In one example, power monitor 120 may sample the voltage signal of eachmain at a predetermined time interval or frequency, such as at 10 MHz,and the current signal for each main at another interval or frequency,such as 10 kHz. The voltage and current signals may be used directly ormay be combined to determine other signals, such as power signals, andthe constituent or combined signals, or other signals may have differentsampling rates. Power monitor 120 may determine other values from thesampled signals, including but not limited to any of, or any combinationof, real power, reactive power, power factor, power quality, apparentpower, or phase between the voltage and current. Determined values maybe root mean square (RMS) or peak.

Power monitor 120 processes electrical signals (such as voltage andcurrent) to disaggregate them or to obtain information about individualdevices in the home. For example, power monitor 120 may determine deviceevents, such as that the television was turned on at 8:30 pm or that thecompressor of the refrigerator started at 10:35 am and 11:01 am. Powermonitor 120 may transmit information about device events to othercomputers, such as server computer 140 or user device 150. Power monitor120 may also determine real-time information about power used byindividual devices in the home and transmit this real-time informationto other computers, such as server computer 140 or user device 150. Forexample, power monitor may determine on predetermined intervals, such asten second intervals, three second intervals, one second intervals, orsub-second intervals, the power used by multiple devices in the home. Asused herein, “real time” means that the information is transmitted to auser without significant delay. For example, when reporting to a userthe wattage used by a light bulb, providing the information to the userwithin several seconds of measurement would be real time.

Power monitor 120 may be a device that is obtained separately fromelectrical panel 110 and installed by a user or electrician to connectto electrical panel 110. Power monitor 120 may be part of electricalpanel 110 and installed by the manufacturer of electrical panel 110.Power monitor 120 may also be part of (e.g., integrated with or into) anelectrical meter, such as one provided by the electric company, andsometimes referred to as a smart meter.

Power monitor 120 may transmit information to other computers using anyknown networking techniques. In FIG. 1 power monitor 120 is shown havinga wireless connection to router 130, which in turn connects to server140 and user device 150. Other networking techniques that may be usedinclude, but are not limited to, wired connections, Wi-Fi, NFC,Bluetooth, and cellular connections. User device 150 need not be on thesame local network and may instead receive information over a wide areanetwork, such as a cellular network, or information served via acloud-computing environment.

Server computer 140 may receive information about devices in the homefrom power monitor 120. For example, server computer 140 may receiveinformation about device events or real-time power usage of devices inthe home. Server computer 140 may store, further process, or facilitatepresentation of the information to end users, including energy users,utility companies, third parties (e.g., parties tracking or regulatingenergy usage), and/or to the host of the methods and systems disclosedherein, such as for various analytic purposes.

User device 150 may be any device that provides information to a userincluding but not limited to phones, tablets, desktop computers, andwearable devices. User device 150 may present, for example, informationabout device events and real-time power usage to the user.

The arrangement and specific functions of the components of FIG. 1provide just one example of how the techniques described herein may beimplemented, but other configurations are possible. For example, powermonitor 120 may perform all the operations of server 140, and powermonitor 120 may directly provide information to user device 150. Inanother example, power monitor 120 may include some or all of thefunctionality of user device 150, and a user may interact directly withpower monitor 120 to obtain information about device events and powerconsumption.

Power Monitor

FIG. 2 illustrates components of one implementation of power monitor120. As noted above, power monitor 120 may be a separate device or bepart of another device such as electric panel 110 or a power meter.

Power monitor 120 may include any components typical of a computingdevice, such one or more processors 280, volatile or nonvolatile memory270, and one or more network interfaces 290. Power monitor may alsoinclude any known input and output components, such as displays,buttons, dials, switches, keyboards, and touch screens. Power monitor120 may also include a variety of components or modules providingspecific functionality, and these components or modules may beimplemented in software, hardware, or a combination thereof. Below,several examples of components are described for one exampleimplementation of power monitor 120, and other implementations mayinclude additional components or exclude some of the componentsdescribed below.

Power monitor 120 may include analog signal processing component 210.Analog signal processing component 210 may include sensors that obtaininformation about electrical signals in electrical panel 110, such assensors for obtaining current and voltage. Analog signal processingcomponent 120 may perform other operations as well, such as filtering tocertain frequency bands or performing dynamic range compression, and mayoutput one or more analog signals.

Power monitor 120 may include digital signal processing component 220.Digital signal processing component 220 may, for example, sample andquantize analog signals output by analog signal processing component210. Digital signal processing component 220 may process multiple analogsignals of different types and may process the different types ofsignals in different ways. For example, digital signal processingcomponent 220 may receive two analog voltage signals and two analogcurrent signals and apply different sampling rates and quantizationschemes to the different signals. Digital signal processing component220 may perform other operations as well, such as noise reduction orsynchronization, and output one or more digital signals.

Electrical event detection component 230 may receive the one or moredigital signals from digital signal processing component 220 and detectelectrical events for further processing. Electrical events include anychanges to electrical signals that may provide useful information aboutthe operation of devices in the house or power usage of devices in thehouse. For example, an electrical event can correspond to manualoperation of a device (such as a user turning on or off a device),automatic operation of a device (such as the dishwasher starting a pumpas part of its operating cycle), a failure in the operation of a device(such as a failure of the dishwasher pump), a change in the mode ofoperation of a device (such as a vacuum cleaner switching from “rug” to“wood floor” mode), a change in operating level of a device (such as anoven increasing in cooking temperature), a change in the amount ofelectrical power used by a device (such as a change in electrical usagein response to a heating or cooling of a component), or otherdevice-related electrical events.

Some electrical events may occur over a relatively short period time orbe transient electrical events. For example, turning on a light bulb maysignificantly change the amount of power or current in an electricalsignal in a short period of time. Other electrical events may occur overa longer period of time and correspond to more gradual changes inelectrical signals. For example, the fan of an air conditioner may havea longer and more gradual ramp up of power or current.

Electrical event detection component 230 may be implemented using anyclassification techniques known to one of skill in the art. In someimplementations, a classifier may by trained in a machine learningenvironment, such as by using data that is already labeled or classifiedby event type. In some implementations, electrical signals may beobtained from houses, and specific electrical events in the data may belabeled automatically, semi-automatically, or manually. Automated orsemi-automatic labeling may be validated or adjusted by manual feedback.Manual labeling may be validated by automatic labeling or by avalidation process involving other individuals. With this data, one ormore classifiers may be trained to automatically recognize electricalevents. The classifiers may include, but are not limited to, neuralnetworks, self-organizing maps, support vector machines, decision trees,random forests, and Gaussian mixture models. The input to theclassifiers may be the digital signals themselves or features computedfrom the digital signals. The classifiers may use electrical eventmodels 200, which may be stored in power monitor 120.

In some implementations, electrical event detection component 230 maylook for changes in the values of electrical signals. For example, asimple change of value of an electrical signal greater than a threshold(volt, amp, watt, etc.) may indicate an electrical event. Changes invalues over time (including rates of change and time-derivativesthereof) are also potentially relevant indicators of electrical events.Some changes in electrical signals may typically occur quickly andothers more gradually. Multiple time scales and multiple thresholds maybe used to identify both transient events and longer term events. Forexample, a 5-watt change in less than one second may indicate atransient event, and a 20-watt change over more than a minute mayindicate a longer-term event.

In some implementations, electrical event detection is performed onceper cycle (e.g., at a frequency of 60 Hz on a typical line). For eachcycle, a window before and after a given cycle may be used to identifyelectrical events. For example, a 20-cycle window may be used to detecttransient events and a 600-cycle window may be used to detectlonger-term events. A value may be computed for each of the before andafter windows (e.g., power) and the change (the change may additive,multiplicative, or other measure of change) in value may be compared toa threshold. The thresholds may be different for shorter and longerwindows, and the thresholds may be different for different electricalmeasurements (power, amps, volts, etc.). The thresholds may also adaptover time. For example, where the recent history of an electrical signalindicates a significant oscillation in the electrical signal, athreshold may be increased so that each individual oscillation of theelectrical signal does not trigger a new electrical event. Thus, themethods and systems disclosed herein contemplate dynamically changing atleast one of a detection window and a recognition threshold in anautomated, electrical event detection and classification system, toimprove recognition of a particular types of event.

For a transient electrical event, the electrical event may be detectedby the electrical event detection component 220 shortly after theoccurrence of the electrical event. For example, the electrical eventmay be output within 20 milliseconds of the occurrence of the electricalevent. For transient events, the electrical event may be detectedquickly, because the information used to identify the electrical eventmay depend on the electrical signal for a short duration window aroundthe electrical event.

For a longer-term electrical event, the electrical event may be detectedby the electrical event detection component 220 significantly after theoccurrence of the electrical event. For example, the electrical eventmay be output several seconds after the occurrence of the electricalevent. For longer-term electrical events, the information required todetect the electrical event may depend on the electrical signal for alonger duration window around the electrical event.

Each of the electrical events may be associated with a time or times.For example, for a transient electrical event, a time may correspond tothe approximate time of the commencement of the electrical event, andfor longer electrical events, the time may correspond to an approximatemid-point of the electrical event, or to starting and ending points ofthe electrical event. More generally, electrical events may also beassociated with a start time, an end time, a duration, a time that theelectrical event was recognized, and a main or mains that the electricalevent was detected from. Electrical events may also be associated withan event type. For example, electrical events may identifiedspecifically as corresponding to certain types of devices, such as amotor, a heating element, a power supply for a consumer electronicdevice, a battery charger, a lamp, or the like. Later processing may usethe event type for more efficient and/or accurate processing.

Electrical event detection component 230 may output a stream ofelectrical events for each electrical signal that is processed. Forexample, if the digital signals include two voltage signals and twocurrent signals, the output may be four separate streams of electricalevents. Alternatively, the output could include a first stream ofelectrical events for the current and voltage signals corresponding tothe first main and a second stream of electrical events for the currentand voltage signals corresponding to the second main. Alternatively, allthe electrical events could be included in a single stream.

Following the electrical event detection, feature generation component235 may determine features corresponding to electrical events. Thefeatures may be useful in subsequent processing for determininginformation about devices from the electrical events. These features mayinclude some of the features used to detect the electrical event itselfand may also include other features that were not used to detect theelectrical event but which may be useful for the subsequent processing.The techniques described herein in are not limited to any particularfeatures, and any features known to one of skill in the art may be used.Each of the features may be computed for individual mains or acombination of mains. Some features may also be computed at differentscales or window lengths. Some features may be computed using a“residual” signal that is computed by subtracting steady state signalcharacteristics that existed before or after the electrical event. Somefeatures may relate to changes to longer duration spectral properties ofan electrical signal. For example, a state of a device may cause energyto appear in a spectral band, and a feature may relate to the energy ora change in the energy in that spectral band.

In some implementations, each electrical event may include multiplefeatures, e.g., approximately 500 features, including but not limited tofeatures relating to comparing power levels (e.g., average, median,maximum, minimum, or logarithmic of the foregoing) in a time periodbefore an event to a time period after the event; a shape of an onset(average power of onset, peak height of an onset, power change over anonset); a value (e.g., average, median, maximum, or minimum) over one ormore time periods; change in real or imaginary components of a spectrum(including at multiple harmonics) over two different time periods;matching a sinusoid to a signal; a maximum slope of a signal; a phaseshift of a signal; a variability of a signal between cycles over a timeperiod; a slope, error, or offset of an exponential decay of a signal;slope or duration of a startup surge; value (e.g., average, median,maximum, or minimum, or logarithmic of the foregoing) of a startup surgeover a time period; ratio of a peak height of startup surge to a minimumvalue after a startup surge; phase offset change at frequency values orbands over two time periods; harmonic values; total magnitude ofharmonic values; harmonic values relative to total magnitude ofharmonics; and onset time differences between mains. These features maybe computed from any of the electrical signals described above,including but not limited to current, voltage, and power signals. Someor all of these features may also be computed on a residual signal aftersubtracting a baseline cycle. Some or all of these features may becomputed for any number of mains.

Features may be transformed either individually or in combination beforebeing processed by the classifier. As an example of an individualfeature transformation, the logarithm of a wattage measurement might beused instead of or in addition to the wattage measurement itself. As anexample of a combination transformation, the electrical signal could bedecomposed into a set of Fourier coefficients or a waveletdecomposition. Furthermore, a subset of the features may be transformedusing techniques such as linear and quadratic discriminants andprincipal components. Features may also be derived from the pattern ofevent timing (for example, the number of events occurring in the past 5seconds or a particular sequence of events, such as a voltage spikefollowed by steady-state current draw) or by adding features associatedwith one event with another event occurring before or afterwards. Thus,in addition to the many individual features that can be calculatedaccording to the above disclosure, various sequence patterns may beidentified and used for or to assist in classification.

Different features for the same electrical event may be computed atdifferent times. For example, some features may require a short windowof the electrical signal around the electrical event and can be computedshortly after the electrical event is detected. Other features mayrequire a longer window around the electrical event and thus featuregeneration component 235 may need to wait and receive additionalportions of the electrical signal before generating other features.

For example, a first feature may require a 10 millisecond window of theelectrical signal, a second feature may require a 0.5 second window ofthe electrical signal, and a third feature may require a 5 second windowof the electrical signal. FIG. 3 illustrates an example timeline 310 forthe occurrence of an electrical event, detection of the electricalevent, and computation of features of the electrical event. FIG. 3 alsoillustrates an example data structure 320 of an electrical event. InFIG. 3, an electrical event is generated at time t1. As described above,the electrical event may be detected by electrical event detectioncomponent 230 at time t2. Electrical event detection component 230 maythen create data structure 320 for the electrical event and add the timeof the electrical event. Note that at this point in the process,features may not yet have been computed and the values of the featuresmay not yet be present in data structure 320. At time t3, featuregeneration component 235 may have received enough of the electricalsignal to compute feature 1 and then add value 1 to data structure 320.Similarly, at time t4, feature generation component 235 may generatefeature 2 and add value 2 to data structure 320, and at time t5,generate feature 3 and add value 3 to data structure 320.

Downstream processing of the electrical event may decide to process theelectrical event before all features have been computed. For example, ifit is desired to determine an outcome quickly, the electrical event maybe processed after feature 1 is computed, even though not all possibleinformation is available. If it is desired to have the most accurateoutcome, downstream processing may not occur until all features of theelectrical event have been computed. In other implementations, theelectrical event may be processed and classification updated each time anew feature is computed.

Device event detection component 240 may receive the one or moreelectrical event streams from electrical event detection component 230with features computed by feature generation component 235. Device eventdetection component 240 may use the features to determine informationabout devices in the home, such as a light turning on or the amount ofpower used by a light that is on. The techniques described herein arenot limited to any particular implementation of device event detectioncomponent 240, and one example implementation is described below.

In some implementations, device event detection component 240 may use asearch process to determine device state changes using the electricalevent stream and one or more models. One implementation of a searchprocess is shown in FIG. 5, which includes search graph 510, electricalevent stream 520, and wattage stream 530.

One example of a model that may be used is a transition model thatdescribes changes in state of a device or an element of a device. Inaddition to a device changing state (a light turning on or off), anelement of a device (a pump in a dishwasher turning on during thewashing cycle, a light inside a refrigerator, a heating element or fanin an oven, and the like) can change state. To capture changes toelements of a device, a transition model may be created for elements ofdevices that can change state. Transition models may be created in ahierarchical fashion. At the highest level, transition models may becreated for classes of devices or classes of elements, such as anincandescent lighting element, a fluorescent lighting element, an LEDlighting element, a heating element, a motor element, a dishwasher, adishwasher with one pump, or a dishwasher with two pumps. Transitionmodels may further be created for classes of devices or elements by aparticular manufacturer (e.g., all dishwashers by a particularmanufacturer may have common features). Transition models may further becreated for a specific version of a device by a specific manufacturer(e.g., Kenmore 1000 dishwasher). Transition models may even further becreated for a specific device (e.g., the Kenmore 1000 dishwasher at MainStreet). In common usage, the “1000” in a Kenmore 1000 dishwasher may bereferred to as a “model” of the dishwasher, but to avoid confusion withmathematical models, the “model” of a dishwasher will instead bereferred to as a “version.”

Some elements may have two states, such as an off state and an on state.For these elements, a transition model may be created for transitioningfrom the off state to the on state and vice versa. For an element withmore than two states (e.g., “off, “low speed,” and “high speed”), atransition model may be created for each allowed state change.

Transition models may be created using any appropriate techniques. Insome implementations, transition models may be created with labeledtraining data (which may be labeled automatically, semi-automatically,or manually, with validation and feedback among combinations of these).The training data may comprise electrical events extracted fromelectrical signals (or optionally the signals themselves) taken fromhouses, which are then labeled as corresponding to an element andaccording the begin state and the end state of the transition. Featuresmay be generated corresponding to the electrical events, and anyclassifier known to one of skill in the art may be used to create thetransition model, including but not limited to neural networks,self-organizing maps, support vector machines, decision trees, logisticregression, Bayesian models (including naïve Bayes models), randomforests, and Gaussian mixture models. A classifier may be trained inthis manner for every state change of every element. The classifier mayreceive the features as input and provide as an output an indication ofwhether the electrical event corresponds to the state change of theelement. Power monitor 120 may store the transition models 202 for eachof the elements and state changes.

In addition to transition models 202, other, non-transition models (notshown in FIG. 2) may be used to identify useful electrical events thatdo not necessarily specifically correspond to a change in state of adevice or element of a device. One type of other model may be a “noise”model. A noise model may recognize portions of electrical signals thatcorrespond to patterns that are present but not useful for understandingthe operation of devices. Once these patterns are detected, they may beremoved from the electrical signal (for example, using subtraction), andremoving these not useful portions of the signal may make it easier forthe transition models to detect device state changes. Another type ofother model may be an “operative” model. An operative model may relateto properties of devices or elements that are not necessarily changingstate but which exhibit varying electrical characteristics while withina state. For example, a motor on a washing machine may cause a varietyof electrical events without changing state. These recognizedoperational characteristics may be used to detect devices as furtherdescribed below, even absent clear identification of a change in state.

Another example of a model is a device model that describes sequentialchanges to the operation of a device. Any appropriate model may be usedfor a device model. In some implementations, a directed graph (weightedor unweighted) may be used. In some implementations, a directed graphmay allow loops that return to nodes representing particular states. Inother implementations, the directed graph may be acyclical, withoutloops that return to particular nodes. FIG. 4 shows an example directedgraph with a beginning state denoted “B,” an end state denoted “E,” andtwo intermediate states denoted “S1” and “S2.” The directed graph ofFIG. 4 could correspond to, for example, a burner of an electric stove.When a person turns on the burner of an electric stove, the heatingelement may not consume power continuously, and may instead consumepower in cycles to maintain a desired temperature. In FIG. 4, thetransition from state B to state S1 may correspond to the initialactivation of the burner. The stove may automatically turn the heatingelement off to transition from state S1 to state S, and then back on totransition from state S2 back to state S1. When the person turns off theburner, the graph transitions from state S1 to state E. In someimplementations, the directed graph may also indicate allowabletransitions for proceeding from one state to another. For example, inFIG. 4, the transition HE1 (indicating that a heating element is turningon) is an allowable transition from state B to sate S1, and thetransition HE0 (indicating that a heating element is turning off) is anallowable transition from state S1 to state S2.

Similarly, other directed graphs may be constructed for other homedevices. For example, a directed graph may be constructed for theheating elements and pumps of a dishwasher. Further, a dishwasher mayhave a different directed graph for each operating mode (“light wash,”“pot scrubbing,” etc.). Simpler devices, such as an incandescent lightbulb, may have a very simple device model or may not have a device modelat all. Device models may also be hierarchical, and device models may becreated for classes of devices, classes of devices by a particularmanufacturer, specific versions of devices by a particular manufacturer,or specific devices in a home. Power monitor 120 may store device models204 or may access device models 204 that are stored externally to powermonitor 120, such as in a cloud storage environment. In someimplementations, device models may also include states corresponding tooperative characteristics that do not necessarily involve transitions.

Another example of a model is a wattage model that indicates theexpected power usage of a device or element over time. For example, whenturning on a 60-watt incandescent light, it may initially consume 70watts and transition to 60 watts over time according to an exponentialdecay at a particular rate. Any appropriate modeling technique may beused to create a wattage model for elements and devices. For example,techniques such as templates, state machines, time-series analysistechniques, Kalman filtering, regression techniques (includingautoregressive modeling), and curve fitting techniques may be used.

In some implementations, a template may be used for a wattage model. Atemplate may characterize the expected power use of a device over time.For example, a template may characterize power usage for each cycleafter a device is turned on. In some implementations, a wattage modelfor a device may be modeled by a Gaussian (or Gaussian mixture model)with a mean and variance that is determined for each cycle since thedevice was turned on. In some implementations, the wattage model mayalso be configured so that the modeling of power usage at one cycle maydepend on the actual or estimated power usage from a previous cycle. Forexample, the wattage model may model the difference between power usageat the current cycle and the previous cycle as another Gaussiandistribution with another mean and variance. Power monitor 120 may storewattage models 206 or access externally stored wattage models 206, suchas from a cloud storage environment.

Another example of a model is a prior model that indicates a likelihoodthat a device or element will be in a particular state given knowninformation. The known information can include any relevant factors,such as time, weather, location, the state of other devices, and usagehistory. A prior model may also model expected durations of states ofdevices and repetitiveness of states of devices, and this informationmay be determined from an individual user's usage history orcollectively from many users' usage history (or a combination thereof).Examples of information used to populate a prior model may include thefollowing: a stove is most likely used during meal times, many devicesare likely to be off in the middle of the night, the furnace is morelikely to be on when it is cold, lights are more likely to be on aftersunset which depends on location, a kitchen light is likely to be on ifit is dark outside and the oven is on, and a person may turn on thebedroom light at 5 am every morning after the alarm goes off. A priormodel may be created for each possible transition of each device ordevice element in the house. Prior models may be trained using labeleddata and may use any appropriate classifiers, such as neural networks,self-organizing maps, support vector machines, decision trees, Bayesianmodels (including naïve Bayes models), linear and nonlinear regression,random forests, and Gaussian mixture models. Power monitor 120 may storeprior models 208 for each of the devices and elements in the house andmay access externally stored prior models 208. Prior models 208 mayoptionally be populated in part by other data sources, apart from datafrom an electrical signal, such as weather information, informationabout sunrise and sunset times, information about the operating state ofdevices acquired from other sources (e.g., by Wi-Fi or through thecloud), and information from other models, such as weather models.

The above models may be used in creating search graph 510, whichindicates possible states of devices in the house over time aselectrical events are processed. Initially, the graph may contain nonodes or just an initial node, such as N1, corresponding to a firsttime. Later, nodes N2-N4 may be added to the graph and indicate thestate of devices in the house at a second time later than the firsttime. There may be some uncertainty as to which of nodes N2-N4correspond to the actual state of the house and each of the nodes may beassociated with a score (such as a likelihood or a probability). Evenlater, nodes N5-N7 may be added to the graph and indicate the state ofdevices in the house at a third time later than the second time. Thegraph may continue beyond nodes N5-N7 with additional edges and nodes.In some implementations, nodes may be added to search graph 510corresponding to operative non-transitions, and a transition to anoperative non-transition node may not change the state of any devicesbetween that node and a previous node.

Node N1 shows an initial or current state of a house as shown by thetable connected to node N1, where the table indicates the state of eachdevice in the house. In this example, the house has a stove, atelevision, and multiple light bulbs. At node N1, the stove is at stateB from FIG. 4, the television is in an off state, and there are 0 lightbulbs on. In this example, the light bulbs in the house are notdistinguished from one another, and only the number of light bulbs thatare on is recorded. An implementation could choose to only record thenumber of light bulbs that are on (instead of identifying particularlight bulbs that are on) because the state of specific light bulbs isnot important to a user.

In FIG. 5, an electrical event stream 520 is shown beneath the searchgraph 510, with electrical events E1 and E2. Each of the electricalevents E1 and E2 may include features from one electrical signal or frommultiple electrical signals. For example, where the device that causedthe electrical event depends on a single main, the electrical event mayinclude feature determined from that main. Where the device that causedthe electrical event depends on two mains, the electrical event mayinclude featured determined from both mains.

When the device event detection component 240 receives electrical eventE1, it processes the electrical event to determine possible statechanges to the devices in the house. Nodes N2-N4 in FIG. 5 show possiblestate changes in response to E1. At node N2, the stove has moved fromstate B to state S1, at node N3, the number of lights on has increasedfrom 0 to 1, and at node N4, the TV has transitioned from an off stateto an on state.

When the device event detection component 240 receives electrical eventE2, it processes the electrical event to determine further possiblestate changes to the devices in the house. In the example, of FIG. 5:node N2 is followed by node N5 where the stove transitions from state S1to state S2; node N3 is followed by nodes N6 and N7, where N6corresponds to a second light being turned on and N7 corresponds to thestove transitioning from state B to state S1; and no nodes follow nodeN4. No nodes may be added following node N4 because a score for N4(discussed in greater detail below) may be low and it is desired toprune this portion of the search graph to save computations.Alternatively, no nodes may be added following node N4, because all ofthe possible transitions following node N4 have a low score. Moregenerally, any pruning techniques may be used to remove nodes fromsearch graph 510 to reduce computational complexity. For example,pruning techniques used for pruning speech recognition graphs may alsobe applied to search graph 510.

The transitions or nodes of search graph 510 may each be associated witha search score. The techniques described herein are not limited to useof any particular search score, and any appropriate search score may beused. In some implementations, each node may have a search score, andthe search score may indicate a combination of all scores along a pathfrom the beginning (e.g., node N1) to the current node. In someimplementations, the search score may be computed using the transitionmodels. For example, between N1 and N2, the stove has changed from stateB to state S1. Using the transition model for this state change andelectrical event E1, a transition score can be computed indicatingwhether E1 corresponds to this transition. In some implementations, thesearch score may be determined from a combination of all transitionscores along a path to the current node.

In some implementations, the search score may be computed using otherscores as well, such as a wattage score computed using the wattage modeland a prior score computed using the prior model. For example, for eachnode that is added to search graph 510, the search score for that nodemay be determined by combining a search score for the previous node, atransition score for the current node, a wattage score for the currentnode, and a prior score for the current node. The search score may bedetermined from the other scores using any appropriate method. Forexample, the search score could be the sum, weighted sum, or product ofthe other scores.

Wattage stream 530 may include wattage values for the power used by alldevices in the house at particular times, such as wattage values W1-W4indicated in wattage stream 530 (wattage values W1-W4 could also bebroken up into wattage values corresponding to individual mains andwattage values corresponding to simultaneous use of both mains). Wattagestream 530 may include wattage values at regular intervals, such as onceper cycle or once per second. The wattage values may be apportionedamong the devices consuming power at that time using the wattage modelfor each device that is consuming power (the apportionment of wattagevalues may also be used to provide a user with information about powerusage of specific devices as explained in further detail below). Forexample, if the total wattage is 65 watts, and a node indicates a 40watt incandescent light and a 25 watt incandescent light are on, thenthe 40 watt light would likely be apportioned 40 watts and the 25 wattlight would likely be apportioned 25 watts.

A wattage score for a node may indicate a likelihood that the observedwattage value could be generated by the state of devices hypothesized bythat node, and the wattage score may be determined using wattage stream530 and wattage models. For example, if templates are used for wattagemodels as described above, the wattage values may be apportioned todevices that are consuming power by maximizing the joint probability ofthe Gaussian models for the appropriate cycle of the template. If thewattage values for each device are proportionate to the wattage modelfor that device, the wattage score will be higher, and if they are notproportionate, the score will be lower. In some implementations, thewattage score may be the joint probability (e.g., according to theGaussian models from templates) that the devices consumed theapportioned wattage.

For example, consider W1 and W2 in FIG. 5. Before electrical event E1,all the devices are off so W1 and W2 should be approximately 0 (subjectto residual power use not attributable to specific devices). Afterelectrical event E1, a single device is now consuming power, and W3should match, or nearly match, the expected wattage of the device thatis consuming power. If W3 is 300 watts, then it may be more likely thatthe stove turned on, as opposed to concluding that a 60-watt light bulbturning on. After event E2, there may be two devices consuming power,and a pair of devices whose expected sum of wattages is close to thetotal will achieve a higher score than a pair of devices whose sum isnot close.

In some implementations, the wattage scores may be stored with thepreceding node of search graph 510. For example, for node N2, thewattage scores for W3 and W4 for the stove being in state S1, the TVbeing off, and no lights being on may be stored in association with nodeN2. If these wattage scores are low, then it may be less likely the N2is the correct path, and node N2 may be pruned from the graph.Conversely, if the wattage scores are high, then it may be more likelythat N2 corresponds to the correct path. Similarly, for node N3, thewattage scores for W3 and W4 may be stored in association with node N3.Since there are no paths following N4, there may not be any wattagescores stored in association with node N4.

The search score may also be computed using a prior score. As notedabove, a prior model may be created for each transition of each device,and the prior score may be computed by inputting known information(time, location, etc.) into the prior model and obtaining thecorresponding prior score.

Different techniques are available for selecting the nodes to follow anexisting node in the search graph. In some implementations, all possibletransitions are always added to the search graph. While this increasesthe computational complexity, it may also increase the accuracy of thesearch. In other implementations, only a subset of possible transitionswill be added to the search graph. For example, the transitionscorresponding to the three highest search scores may be added, or alltransitions with search scores higher than a threshold may be added. Insome implementations, only valid transitions may be added to the searchgraph (e.g., you cannot turn on a television that is already on).

The search implemented by device event detection component 240 mayoperate in different modes for achieving different objectives. Forexample, one mode may be a real-time mode where the search isimplemented to determine as quickly as possible a transitioncorresponding to an electrical event. Another mode may be a historicalmode where the search is implemented to have higher accuracy and it isacceptable to have higher latency. Device event detection component 240may implement multiple modes simultaneously or start and stop individualmodes upon request.

In real-time mode, the search may be modified to reduce the amount oftime between receiving an electrical event and determining which node ornodes to add to search graph 510. One modification to the search relatesto deciding when to process an electrical event. As described above,feature generation component 235 may output features of an electricalevent at different times. For a real-time search, device event detectioncomponent 240 may add additional nodes to search graph 410 based on asubset of features that are available sooner and ignore other featuresthat are not available until later. Alternatively, device eventdetection component 240 may add additional nodes to search graph 510based on an earliest subset of features that provides a sufficientconfidence level. For example, a first feature (or first set offeatures) for electrical event E1 may indicate that it is most likelythat the stove transitioned from state B to state S1, but the confidencelevel may be low (such as below a threshold). Device event detectioncomponent 240 may choose to delay processing the electrical event untilreceiving a second feature (or second set of features) for electricalevent E1. Processing the electrical event with both the first and secondfeatures may indicate that the stove transitioned from state B to stateS1 with a higher confidence level (above a threshold), and nodes may beadded to the search graph in response to processing the second featurefor the electrical event.

Additionally, in real-time mode, the search may be modified to only adda single node in response to an electrical event. When adding a node inresponse to the electrical event, only the highest scoring node may beadded. Adding only a single node for each electrical event may decreaserequired computations and increase speed.

In historical mode, the search may be modified to increase the accuracyof determining device events. One modification to the search may be toalways wait for all features of an electrical event before processingthe electrical event to add nodes to the search graph. By waiting forall features an electrical event, device event detection component 240may have the greatest amount information available before deciding whichnodes to add to search graph 410. Alternatively, the search may bemodified to add additional nodes to the graph based on a subset offeatures of an electrical event that provide a sufficient confidencelevel where the confidence level is higher than the confidence levelused for the real-time search.

Additionally, in historical mode, the number of nodes added to the graphmay be increased or a pruning threshold may be reduced. By adding morenodes to graph and performing less pruning, it is more likely thatdevice event detection component 240 will correctly determine thecorrect transition for an electrical event.

For both the real-time mode and the historical mode, the electricalevents may be processed out of order with respect to the time at whichthe electrical events occurred. For example, electrical event E1 mayoccur at time 1, and features may be generated at time 5, 10, and 15.Electrical event E2 may occur at time 2, and feature may be generated attime 3, 4, and 5. In real-time mode, electrical event E2 may beprocessed at time 3 and electrical event E1 may be processed at time 5even though electrical event E1 occurred first. Similarly, in historicalmode, electrical event E2 may be processed at time 5 and electricalevent E1 may be processed at time 15 even though electrical event E1occurred first. Additionally, in some implementations, nodes for anelectrical event may be added to search graph 510 at different times.For example, in response to electrical event E1, N2 may added at a firsttime based on a first set of features for E1, and N3 may be added at asecond time based on a second set of features for E1.

In addition to determining state transitions of devices, device eventdetection component 240 can also determine the power used by each of thedevices at regular (or irregular) time intervals. For example, deviceevent detection component 240 may compute the power used by each devicefor each wattage value in wattage stream 530. As described above, deviceevent detection component 240 can apportion a wattage value, such as W3,among the devices that are active at that time. Since different nodes ofthe graph correspond to a different set of active devices, theapportionment of power among active devices may be stored at acorresponding node as described above.

Device event detection component 240 may thus produce an estimate ofpower used by individual devices in addition to device events. Powermonitor 120 may transmit this information to server 140 or user device150.

Real-Time Architecture

When power monitor 120 transmits device information to server 140, thearchitecture of the network connections between power monitor 120 andserver 140 may be configured to enhance real-time transmission ofinformation. FIG. 6 shows one implementation of a system 600 withnetwork connections between power monitor 120 and two server computers,denoted API server 610 and monitor bridge 620. In addition, user device150 may also have network connections between API server 610 and monitorbridge 620. API server 610 and monitor bridge 620 may include any of thecomponents described below for server 140.

In some implementations, the information transmitted over the networkconnections may depend on whether a user is currently viewinginformation about devices, such as via an app on user device 150 or byviewing a web page with user device 150. When the user is not viewingdevice information, system 600 may operate in a historical mode andpower monitor 120 may not need to provide real-time information. When auser is viewing device information, system 600 may operate in areal-time mode and power monitor 120 can provide real-time informationso that the user is always viewing up to date information.

In some implementations, monitor bridge 620 facilitates the transmissionof real-time information from power monitor 120 to user device 150. Toallow faster switching between historical mode and real-time mode,network connection C1 may be a continuous network connection. Forexample, power monitor 120 can be configured so that the connection ismaintained even when not in use. For example, it may automaticallyconnect to monitor bridge after being powered on, and configured so thatit if ever loses the connection to monitor bridge 620, it willimmediately attempt to reestablish the connection. Other connections,such as connections C2-C4 may not be continuous connections, and theseconnections may be opened when a device needs to transmit informationand closed upon the completion of the transmission (or shortlyafterwards, upon expiration of a time out, or some other criterion).

In some implementations, when system 600 is in historical mode,connection C1 will not be used to transmit information even thoughconnection C1 is maintained between power monitor 120 and monitor bridge620. In the historical mode, power monitor 120 may periodically (e.g.,every 15 minutes) open connection C2 to API server 610 and provideupdated information since the last transmission via connection C2. Aftertransmitting the information, power monitor 120 may close connection C2.API server 610 may store the information so that it may later beaccessed by the user, such as by using user device 150.

When system 600 is in historical mode, the search by device eventdetection component 240 in power monitor 120 may also operate inhistorical mode and provide more accurate information about devices inthe home. Although the historical mode search by power monitor 120 mayincrease a delay between the occurrence of electrical events and thedetermination of information about the electrical events, because power120 is only providing information to API server 610 on a periodic basis,the delay caused by the historical mode search may be acceptable.

When a user accesses device information, such as by opening an app orviewing a web page with device 150 (or some other device), system 600may switch to real-time mode. In some implementations, monitor bridge620 sends an instruction to power monitor 120 to start sending deviceinformation in real time, and user device 150 is sent an instruction toconnect to monitor bridge 620. Upon power monitor 120 receiving theinstruction, the search by device event detection component 240 maybegin to operate in real-time mode, and power monitor 120 may transmitreal-time device information to monitor bridge 620. Monitor bridge 620receives the information and may immediately send it to user device 150so the real-time information may be presented to the user. Monitorbridge 620 may optionally modify or add to the real-time informationthat is sent to user device 150. For example, the real-time informationreceived from power monitor 150 may include device identifiers fordevices in the home but may not include device names. Monitor bridge 620may add device names to the real-time information so that theinformation is more readily understood by the user.

When a user stops viewing device information, for example by closing anapp or navigating to a different web page, system 600 may switch back tohistorical mode. In some implementations, monitor bridge 620 mayinstruct power monitor to stop transmitting real-time information, andthe search by device event detection component 240 in power monitor 120may also switch back to historical mode. Although continuous connectionC1 may not be used in historical mode, the connection may remain open tofacilitate a switch back to real-time mode in the future.

In some implementations, more than one monitor bridge 620 may beavailable, and power monitor 120 and user device 150 may need toidentify a particular monitor bridge to connect to. In someimplementations, power monitor 120 and user device 150 may query APIserver 610 to obtain an address of a monitor bridge to connect to, andpower monitor 120 and user device 150 may then connect to monitor bridge620 using that address. In some implementations, a first monitor bridgemay need to instruct a power monitor 120 and user device 150 toreconnect to a second monitor bridge (e.g., for load balancing ormaintenance of a monitor bridge). When a first monitor bridge needs toinstruct a power monitor 120 and user device 150 to reconnect to asecond monitor bridge, it may send a disconnect instruction along withan address for the second monitor bridge, and power monitor 120 and userdevice 150 may then connect to the second monitor bridge using theaddress.

Monitor bridge 620 and API server 610 may also interact with one or morebackend services 630 to provide services to user device 150 and powermonitor 120. Examples of backend services include providing alerts touser device 150, storing and retrieving information about specific usersor devices that are stored in power monitor profiles 804 (discussedbelow), storing usage data 806 received from power monitors (discussedbelow), and providing updated models to specific power monitors(discussed below).

Presentation of Device Information

FIGS. 7A-7G show several examples of information that may be presentedto a user based on information received from power monitor 120. FIG. 7Ashows a display 700 that may correspond to an initial display of an appor the main page of a website. The top portion 701 of display 700presents several graphical elements 702 that indicate power usage ofseveral devices in the house. As shown, graphical elements 702 arecircles, but any suitable graphical representation may be used. Thesize, color, shading, highlighting, or other feature of the graphicalelements 702 may indicate the amount of power used by the correspondingdevices. For example, the area of the circle may indicate the amount ofpower. Alternatively, the volume of a sphere with the same diameter maycorrespond to the amount of power. By using a non-linear scale, it maybe easier to represent devices with significantly different powerusages. Where user device 150 is receiving information in real time, thegraphical elements 702 may also be updated in real time so that the useris viewing the information without significant delay from themeasurement of the information. In some implementations, graphicalelements 702 may move or bounce into each other to provide the user witha visually appealing display. The top portion of the display may alsoinclude the total power 703 used by all devices in the house, and thismay also be presented in real time. For example, if a user turns off alight in the house, total power 703 may indicate the reduced powerwithout significant delay. The power values may correspond to an amountof energy consumed during a time interval, such as one second or oncecycle.

The devices presented in the top portion 701 may be selected accordingto different criteria. For example, in some implementations, the devicespresented in top portion 701 may represent the devices consuming themost power or may be devices selected by the user. In someimplementations, the user may specifically exclude some devices fromappearing in the top portion.

In some implementations, the specificity in naming the devices presentedin the top portion 701 may be determined by a confidence in thecorrectness of the device identification, and hierarchical models may beused to determine the appropriate specificity. In some implementations,a lowest level model in hierarchy that has a sufficient confidence maybe used to name a device. For example, if a general “lighting model” hasa sufficiently high confidence score, but all lower level models (e.g.,LED lighting, incandescent lighting, etc.) do not, then the device maybe named as a light. If, however, the LED lighting model has asufficient confidence score, the device may be named as an LED light.

The bottom portion 704 of display 700 may present device events or otherinformation about devices as list items 705. For example, in someimplementations the bottom portion 704 may present devices that havechanged state (e.g., the coffee maker turned on), the current state of adevice (e.g., the dryer is on), information about the number of uses ofa device over a time period (e.g., that dryer has been used 5 times inthe last week), an input element to create an alert based on a statechange of a device (e.g., the user may want to create an alert to knowwhen the clothes washer is completed so he or she can put the clothes inthe dryer), or a warning that a device has been on for a certain periodof time (e.g., that a hair straightener has been on for half an hour).Each item of the list may have additional information such as a timeassociated with the device event or power consumption relating to thedevice event.

In some implementations, a user may perform actions to view otherinformation. For example, a user may select (touch via a touch screen orclick or mouse-over with a mouse) one of the graphical elements 702 toview additional information about that device. A user may select listitems 705 to view more information about them. A user may swipe in adirection to see other displays of information.

FIG. 7B shows another display where the status of devices in the houseis shown as a list. For example, all of the devices in the house may bepresented in alphabetical order, devices selected by the user may bepresented, or devices except those excluded by a user may be shown.Information about each device may be shown, such as whether the deviceis on or off or the amount of power being consumed by the device. Insome implementations, a user may select a list item to see moreinformation about that device.

FIGS. 7C and 7D show examples of displays with additional informationabout individual devices. These displays may be accessed, for example,by selecting the corresponding devices in FIG. 7A or 7B. A display forinformation about a device may include, for example, a name indicating atype of device (e.g., washer), an icon indicating a type of device, apicture of the actual device, the manufacturer and/or version of thedevice, the location of the device in the house, the amount of powerbeing consumed by the device, the state of the device (e.g., on or off),the last time the device was used, the length of time the device isbeing used, the percentage of power usage attributable to the device, orthe number of times the device has been used over a time period. Inaddition, the display for information about a device may include userinputs to allow a user to indicate whether the device should appear onother displays (such as FIGS. 7A and 7B), to obtain further informationabout the device (such as power usage and other information relating topast usage of the device), and to allow the user to create alertsrelating to the device (e.g., state changes of the device or if thedevice is left on for greater than a period of time).

Some devices in a user's home may not be identifiable. For example, if auser purchases a new device, it may be referred to as an unknown device.Unknown devices may be listed in various displays with the name “UnknownDevice” and a question mark for an image. An unknown device may not beidentifiable, but power monitor 120 may be able to recognize it as adevice and determine some information about it, such as when it isturned on or off and how much power it consumes. FIG. 7E shows anexample display for an unknown device when the user selects “Unknown” or“Unknown Device” from FIG. 7A or 7B. The display for the unknown devicemay provide some information about the unknown device, such as whetherit is on or off and how much power the unknown device is consuming. Thedisplay for the unknown device may also include a user interface forproviding further information about the unknown device, such as thename, type of device, make, version, location, etc.

In some implementations, a user may be able to take pictures or video ofdevices in the house, and object recognition techniques may be used toautomatically identify a user's devices. For example, a user could walkaround the house and take pictures or video of kitchen appliances, waterheater, furnace, washer, dryer, and television to quickly identify manyof the large appliances in the house. The user could also be asked toprovide a “tour” of the devices in the house, switching devices on andoff and signifying through the user interface which device state waschanged at the time of the change.

In some implementations, a user may be asked for assistance withidentifying information about devices that are always on. Some devicesare always on or nearly always on by their nature (e.g., refrigerator,Wi-Fi router, etc.), and other devices do not completely turn off evenwhen they appear off to a user (e.g., television). For example, a usermay be instructed to briefly unplug specific devices, such as thetelevision and Wi-Fi router, wait for an amount of time, and theninstructed to plug the device back in. With this information, powermonitor 120 can determine information about electrical usage of devicesthat are always or nearly always on and then provide more informativereports to the user. For example, a switching power supply of atelevision may have specific characteristics, and once thosecharacteristics are determined, power monitor 120 may be able todetermine information about electrical usage of the television on anongoing basis.

In some implementations, a user may be asked questions to help identifydevices in the house. The questions may be asked before the userinstalls power monitor 120 or after power monitor 120 is installed andpreliminary data is collected. Questions could be at a high level, suchas yes/no questions regarding whether the user owns particular types ofdevices (e.g., hot tub, aquarium, humidifier, etc.). Questions could bemore specific and ask the user to provide manufacturers and/or versionsof devices in the house. Questions could also relate to asking a user toconfirm whether power monitor 120 has accurately discovered devices inthe house (device discovery is explained in further detail below).

In some implementations, the display for an unknown device may implementa procedure to assist a user in determining which device in the housethe unknown device corresponds to. For example, the display for anunknown device may contain a button “Identify Me” (not shown in FIG.7E). The user can push (or hold down, tap, or any other form of userinput) this button and then change the state of a device in the house byturning it on or off. Power monitor 120 can then compare the electricalevent received shortly after the button press with an electrical eventfrom the unknown device to determine if the two are the same, and theresults may then be presented on the display for the unknown device,such as “Yes, this is the unknown device” or “No, that is not theunknown device.” In this manner, a user can repeatedly try devices untilthe unknown device is determined. Thus, more generally, a user mayvalidate or negate information initially presented based ondeterminations made by a power monitor 120, such as confirming that aparticular device is, in fact, the oven, a light bulb, or the like.

After determining which device the unknown device corresponds to, theuser may edit information about the device. For example, in FIG. 7E, theuser may press edit button 706 to activate an edit mode (not shown). Inthe edit mode, a user may enter information about the device, includingbut not limited to a name, type, manufacturer, version, and location(room or floor of the house). The user may then press edit button 706 asecond time to save changes.

Additional information that may be presented to a user includes adisplay of historical power usage as shown in FIG. 7F. This display maybe accessed, for example, by touching the number for total power 703from FIG. 7A. In displaying historical power usage of all devices, anypresentation format may be used, including but not limited to barcharts, line charts, or a list of numbers. Different granularities maybe available, such as hourly, daily, weekly, or monthly. For exampleFIG. 7F shows monthly power usage for 5 months. In some implementations,a user may change the time scale, for example by pinching to show alarger time scale or splaying to show a smaller time scale. In someimplementations, a user may touch one of the bars of a bar graph toobtain the number of watts corresponding to the bar.

Historical power usage of individual devices may also be presented to auser as shown in FIG. 7G, where historical power usage of a washer isshown. Any of the techniques for presenting historical power usage foroverall power usage in FIG. 7F may also be applied to present historicalpower usage of individual devices.

The relative power usage of individual devices may also be presented tohelp the user understand how much power devices are consuming comparedto one another. In some implementations, pie charts may be used to showrelative power usage. For example, a pie chart may be shown where theentire pie chart represents the total power usage over a period of time(e.g., the last month). The pie chart may present slices for each devicein the house, and a user may touch an individual slice to obtainadditional information about that device or the power usage by thatdevice. In some implementations, a large number of devices may result ina complex pie chart, and classes of devices may be presented instead ofsome or all of the individual devices. For example, the slices for allof the incandescent light bulbs may be replaced with a single slice forincandescent light bulbs. In some implementations, a user may be able tozoom into a portion of the pie chart to more easily view the powerconsumption of individual devices.

Device Discovery and Model Updating

The foregoing provides example implementations of how power monitor 120may be able to recognize device events for devices in the home. Theperformance of power monitor 120 may be improved, however, by usingmodels that are specific for or adapted to a particular home. First,power monitor 120 may have models that correspond to the types orclasses of devices in the home. If it is known that the home includes ahot tub, then a model that is able to determine device information for ahot tub may be added to power monitor 120. Second, power monitor mayhave models corresponding to the specific make and/or version of devicesin the home. For example, the home may have a Kenmore 1000 microwave,and models particular to this microwave may be added to power monitor120. Third, a specific manufacturer and version of a device may operatedifferently in different homes due to variances in manufacture, thespecific electrical grid in the home, and other factors. Power monitor120 may additionally have models that are adapted to the specificoperation of the Kenmore model 1000 microwave in a specific home.

FIG. 8 illustrates components of one implementation of a server 140 fordiscovering new devices in a home and updating models for devices in ahome. In FIG. 8 the components are shown as being on a single servercomputer, but the components may be distributed among multiple servercomputers. For example, some servers could implement device discoveryand other servers could implement model updating. Further, some of theseoperations could by performed by power monitor 120 or other devices in ahome.

Server 140 may include any components typical of a computing device,such one or more processors 880, volatile or nonvolatile memory 870, andone or more network interfaces 890. Server 140 may also include anyinput and output components, such as displays, keyboards, and touchscreens. Server 140 may also include a variety of components or modulesproviding specific functionality, and these components or modules may beimplemented in software, hardware, or a combination thereof. Below,several examples of components are described for one exampleimplementation, and other implementations may include additionalcomponents or exclude some of the components described below.

Server 140 may include device discovery component 810 for discoveringinformation about devices in a home. For example, when power monitor 120is first installed in a home, it may not have any information aboutdevices in the home or it may only have information about classes ofdevices that are (or may be) in the home but not have information aboutspecific devices. Device discovery component 810 can receive informationabout electrical signals in a home, determine information about devicesin the home, and then send updated models to the home for use by powermonitor 120.

In some implementations, device discovery component 810 may receiveother information in addition to information about electrical signals.Where power monitor 120 is connected to a home network (either wired orwirelessly and with permission of the user), power monitor may be ableto determine information about other devices on the home network. Forexample, power monitor may be able to determine information about themanufacturer and version of the wireless router is it connected to.Power monitor may also be able to determine information about otherdevices on the home network, such as home computers, mobile devices(e.g., phones, tablets, watches, glasses), and devices relating to homeautomation or the Internet of things (e.g., smart thermostats and otherdevices for controlling lights, locks, security systems, cameras, andhome entertainment systems). Power monitor 120 may also be able toobtain information about devices in the home by monitoring other networkprotocols, such as Wi-Fi, NFC, Bluetooth and ZigBee. An app on userdevice 150 may also be configured to determine information about deviceson local networks, such as Wi-Fi, Bluetooth and ZigBee. Device discoverycomponent 810 can receive this information about devices on the localnetworks to improve the models sent to power monitor 120. For example,device models for a user's Wi-Fi router and for charging a user'sparticular smart phone may be added to the user's power monitor toimprove the ability of the power monitor to determine the electricityusage of these devices.

Device discovery component 810 can receive any relevant information frompower monitor 120 and the information received may vary over time. Forexample, when power monitor 120 is first installed in a home, devicediscovery component 810 may receive a continuous stream of electricalsignals in the home to determine characteristics of electrical signalsin the home and to discover devices in the home. Continuously streamingelectrical signals from a home may consume significant network andprocessing resources and thus may be performed for only a limited periodof time.

Device discovery component 810 may receive information about electricalevents from power monitor 120. When power monitor 120 is first installedin a home, device discovery component 810 may receive a continuousstream of information about electrical events to discover devices in thehome. As devices are discovered and power monitor 120 updated withadditional models, the information about electrical events transmittedto device discovery component 810 may be reduced. For example, devicediscovery component 810 may receive only information about electricalevents that do not correspond to devices known by power monitor 120.

Device discovery component 810 may also receive information about deviceevents determined by power monitor 120. For example, power monitor 120may determine that a dishwasher started at a particular time and thisinformation may be received by device discovery component 810. Thisinformation may be used by device discovery component 810 to update andmake corrections to power monitor models. For example, it may be thatthe device event was incorrectly determined to be a clothes washerstarting, and device discovery component 810 can update the models toreduce the likelihood of this error from happening again. In someimplementations, device discovery component 810 may receive all or asubset of search graph 510 in one or more modes. For example, devicediscovery component 810 may receive a best path through search graph 510for a historical mode search.

Device discovery component 810 may also receive information generated bythe user or feedback provided by a user. As described above, user device150 may provide a user interface where the user is requested to helpidentify devices in the house. Power monitor 120 may thus provideelectrical signals and/or electrical events that have been manuallylabeled by the user. This labeled data may be used to train models forthis particular user and other users. A user may also provide feedbackcorrecting identifications made by power monitor 120. For example, powermonitor may have identified a dishwasher as a Kenmore dishwasher wherethe dishwasher was actually a Whirlpool dishwasher. The user feedbackmay be used in combination with the electrical signal and/or electricalevent to improve models for both Kenmore and Whirlpool dishwashers.

Device discovery component 810 may use device discovery models 800 todiscover devices in a home. Device discovery models 800 may include ahierarchy of models. For example, discovery models 800 may includemodels that generally correspond to the operation of most or alldishwashers, models that correspond to a subset of all dishwashers(e.g., dishwashers with one pump or dishwashers with two pumps), modelsthat generally correspond to most or all versions of dishwashers by aspecific manufacturer, and models for specific versions of dishwashersby a specific manufacturer. In this manner, device discovery component810 may provide the best available information to power monitor 120. Ifa user purchases a version of a dishwasher that was just released,device discovery component 810 may not be able to determine the versionof the dishwasher, but may be able to determine the manufacturer of thedishwasher, or at least determine correctly that the device is adishwasher. In some implementations, device discovery component 810 mayuse transition models 202 and device models 204 for discovering newdevices, and in some implementations, device discovery component 810 mayuse variations of transition models 202 and device models 204, or mayuse completely different models.

In some implementations, device discovery component 810 receives astream of information about electrical events. The stream of electricalevents could correspond to all electrical events detected by powermonitor 120 or could include only electrical events that do notcorrespond to previously discovered devices. Device discovery component810 may compare the stream of electrical events against one or moredevice discovery models 800 to determine a device corresponding to theelectrical events. Device discovery component 810 may compare theelectrical events against all device discovery models 800 to determine adevice, or could proceed in a hierarchical fashion by first determiningthat the electrical events correspond to a dishwasher, then to adishwasher by a particular manufacturer, and then to a specific versionof a dishwasher by the particular manufacturer.

In some implementations, device discovery component 810 may create adiscovery graph using an electrical event stream, transition models, anddevice models. FIG. 9 shows an example electrical signal with electricalevents from two devices, and FIG. 10 shows an example of discovery graph1000 created for the electrical signal of FIG. 9. Device discoverycomponent 810 may receive electrical signal 900 and determine electricalevents in electrical signal 900 or may instead receive an electricalevent stream where the electrical events are determined elsewhere. Inthe example of FIG. 9, the electrical signal may correspondapproximately to electrical signals received from the burner of anelectric stove and an incandescent light bulb. The burner may berepresented by a heating element, and electrical event HE1 maycorrespond to the heating element transitioning from an off state to anon state and HE0 may correspond to the heating element transitioningfrom the on state to an off state. Electrical event I1 may correspond toan incandescent light bulb transitioning from an off state to an onstate and electrical event I0 may correspond to the incandescent lightbulb transitioning from an on state to an off state. Electrical events910-980 show a possible sequence of electrical events generated by aheating element and an incandescent light bulb.

As described above, FIG. 4 illustrates an exemplary state model for anelectric burner of a stove. Device discovery component 810 may create adiscovery graph using an electrical event stream and the device model ofFIG. 4 to determine if the sequence of electrical events in theelectrical event stream includes a burner.

Discovery graph 1000 begins at node 1010, where node 1010 corresponds tothe initial state, state B, of the device model for an electric burner,and state B is indicated with a diamond. The first electrical event inthe electrical event stream is electrical event 910. The transitionmodels may be used to determine that electrical event 910 corresponds tothe transition HE1. For example, this may be accomplished by applyingall of the transition models to electrical event 910 and selecting thetransition whose transition model produces the highest score. Thetransition HE1 may be compared against discovery graph 1000 to determineif HE1 is an allowable transition from any current node in the discoverygraph. Since node 1010 corresponds to state B and HE1 is an allowabletransition from state B to state S1, node 1011 may be added to discoverygraph 1000, where node 1011 corresponds to state S1 and is indicatedwith a solid circle.

The next electrical event is electrical event 920, and the transitionmodels may be used to determine that electrical event 920 corresponds tothe transition I1. Transition I1 does not correspond to any validtransitions from nodes of discovery graph 1000 so no nodes may be addedin response to electrical event 920.

The next electrical event is electrical event 930, and the transitionmodels may be used to determine that electrical event 930 corresponds tothe transition HE0. Transition HE0 is not an allowable transition fromnode 1010 but it is an allowable transition from node 1011. Node 1011corresponds to state 51, and HE0 is an allowable transition from state51 to both state S2 and state E. Since both of these transitions areallowed, two nodes are added to discovery graph 1000: node 1012 and node1013. Node 1012 corresponds to the transition to state S2 and isindicated with an empty circle. Node 1013 corresponds to the transitionto state E and is indicated with a square.

The next electrical event is electrical event 940, and the transitionmodels may be used to determine that electrical event 940 corresponds tothe transition HE1. As above, HE1 is an allowable transition from node1010, and thus node 1060 may be added to discovery graph 1000, wherenode 1060 corresponds to state S1. Electrical event HE1 is also anallowable transition from node 1012, and thus node 1014 is also added todiscovery graph 1000, where node 1014 corresponds to state S1.

FIG. 10 continues to show allowable transitions for electrical events950-980. For each of these electrical events, the correspondingtransitions are determined, and nodes are added to discovery graph 1000for allowable transitions. Note that for clarity, transitions followingnodes 1018, 1020, 1031, 1043, 1050, 1060, and 1070 are indicated withellipses.

Discovery graph 1000 may be used to identify a device corresponding toelectrical event stream 1005. In some implementations, discovery graph1000 reaching the end state of a device model indicates that thesequence of electrical events likely corresponds to the device of thedevice model. In some implementations, additional information may beconsidered. For example, other information may be availablecorresponding to a device model, such as an expected duration that adevice remains in a particular state and an expected change in powerconsumption caused by an electrical event. For the device model of FIG.4, the length of time that the device stays in state S1 may be limitedto 1-5 seconds. For the transition from node 1011 to node 1050 in FIG.10, the length of time that the device stays in state S1 may be 10seconds. Because this duration exceeds the allowable duration, thetransition from node 1011 to node 1050 may not be an allowabletransition and this transition may be excluded from discovery graph1000. Similarly, a change in power consumption caused by an electricalevent and any other relevant factors may be used to determine whether asequence of electrical events corresponds to a device. Any of theinformation used in creating search graphs may also be used withdiscovery graphs. For example, transition scores, wattages scores, andprior scores may all be used to determine whether a sequence ofelectrical events corresponds to a device.

Where discovery graph 1000 includes multiple paths that reach the endstate of a device model, one of the multiple paths may be selected as amost likely path corresponding to the actual operation of the device.For example, in FIG. 10, the paths ending at nodes 1013, 1016, 1019, and1021 may all correspond to valid state transitions for the burner. Othercriteria may be used to select one of these paths as most likelycorresponding to operation of the burner. For example, longer paths maybe preferred over shorter paths, so the path ending at node 1019 may bepreferred over the paths ending at nodes 1013 and 1016. Additionally,the path ending at node 1019 may be considered more likely than the pathending at 1021 based on the durations for the states of the devicemodel. In some implementations, each path of a discovery graph thatreaches an end state of a device model may be assigned a score. Thescore may be computed using any relevant information, including but notlimited to scores produced by transition models, path lengths, stateduration constraints, and power constraints. The path with the highestscore may then be selected as the most likely path.

A consistency of nodes along a path may also be used to score a path orto select a path from several paths that reach an end state. Forexample, for each instance of the HE1 event, it may be expected thepower consumed during the event and/or the length of time in state S1 issimilar for each occurrence of state S1. Accordingly, a path withgreater consistency may receive a higher score than a path with lowerconsistency.

Once a most likely path is determined from discovery graph 1000, theelectrical events corresponding to the most likely path may be removedfrom electrical event stream 1005. For example, if the most likely pathis the path ending at node 1019, then removing these electrical eventsfrom electrical event stream 1005 would leave only electrical event I1920 and electrical event I0 970. These remaining electrical events maythen be processed with another discovery graph 1000 to discover anotherdevice.

To determine that a device that corresponds to a sequence of electricalevents, a discovery graph may be created for a variety of devices. Insome implementations, discovery graphs may first be created for classesof devices to determine at a high level whether the device correspondsto a class of device, such as a refrigerator, stove, dishwasher, etc.Where only one discovery graph reaches an end state, the correspondingdevice class may be selected. Where more than one discovery graphreaches an end state, the device class may be selected according to agreatest score. After determining the class of device, additionaldiscovery graphs may be created to determine more specific informationabout a device. For example, discovery graphs may be created for eachmanufacturer of dishwashers, or discovery graphs may be created for eachknown version of dishwasher. As above, the device may be selected by ahighest scoring discovery graph that has a path that reaches an endstate.

Once the device is determined from the sequence of electrical events,models may be selected for transmission to power monitor 120. Forexample, electrical event models, transition modes, device models,wattage models, and/or prior models that contain information about thediscovered device may be transmitted to power monitor 120.

In addition to discovering new devices, server 140 may also updatemodels for known devices and adapt models for known devices. Models maybe updated for a variety of reasons: research and development effortsmay determine new models that perform better than previous models, newmodels may be created as new devices become available on the market,models may be adapted to specific devices to account for variances inmanufacturing, and models may be adapted as the electrical properties ofdevices drift over time (e.g., caused by wear of devices or changes inthe quality of the electrical lines in the house). For example, a usermay purchase the latest version of a Kenmore dishwasher. At the timethat server 140 discovers the dishwasher, server 140 may not yet have adevice model for the latest version of a Kenmore dishwasher. Server 140may provide power monitor 120 with a device model for Kenmoredishwashers. Later, when server 140 has updated its device discoverymodels, it may again perform device discovery to determine the specificversion of a Kenmore dishwasher and provide that device model to powermonitor 120.

Server 140 may store power monitor models 802, which may includeelectrical event models, transition models, device models, wattagemodels, and prior models. Power monitor models 802 may include any ofthe type of models discussed above including but not limited to modelsfor classes of devices and elements (e.g., dishwashers), models fordevices and elements by a particular manufacturer (e.g., dishwashers byKenmore), models for a particular version of a device by a particularmanufacturer (e.g., a Kenmore version 1000 dishwasher of a certainvintage), and models for specific devices (e.g., the Kenmore version1000 dishwasher at 100 Main Street). The models may be updated over timeand adapted to specific power monitor users as described below.

Server 140 may store usage data 806 received from power monitors inhomes. Usage data 806 may include, for example, electrical signalsprocessed by power monitor 120, portions of electrical signals processedby power monitor 120, portions of electrical signal processed by powermonitor 120 that correspond to electrical events, features generatedfrom electrical signals or electrical events, device events detected bypower monitor 120, or all or portions of search graphs created by powermonitor 120. To ensure the privacy of end users, this usage data may beanonymized (removing personally identifying information) and/or retainedfor a limited period of time. Usage data 806 may be used to update oradapt models as described below.

Server 140 may store power monitor profiles 804 for users of powermonitors. Power monitor profiles 804 may store any relevant datarelating to the operation of a power monitor 120 by a particular userwith the knowledge and permission of the user. Data that may be storedin a power monitor profile includes, for example, a purchase and/orinstallation date of a power monitor, a list of devices discovered bydevice discovery component 810, dates of discovery of devices, ageographic location of a power monitor, a number of people residing in ahouse and demographic information about the people, historicalinformation about aggregate power usage and power usage by individualdevices, and historical information about device events such as devicesturning on or off or changing state.

A power monitor profile may also store models that are specific to aparticular user. As described below, models may be updated or adapted toa specific user's house and specific devices in a user's house. Thehouse-specific models may be stored (or a link to the models may bestored) in a user's power monitor profile. Usage data of a user may alsobe stored (or a link to the usage data may be stored) in the user'spower monitor profile. The usage data may be labeled by the user or maybe labeled automatically by a company that creates the power monitormodels for a user. This usage data may be used to create house-specificmodels for a user as described below.

The model updaters 820-860 may be used to update and adapt existingmodels to create better house-independent models or to create betterhouse-specific models. Model updaters 820-860 may do model updates on aperiodic basis. Shortly after a user obtains a power monitor 120, modelupdaters 820-860 may operate more frequently, e.g., once a day, as itmay be expected that receiving data from a new user will allowhouse-specific models to improve quickly. When power monitor 120 isfirst installed, the models used may be more general, and by collectinghouse specific data, models can be constructed that perform betterbecause they are built with data from the user. As time goes on, modelsmay be updated less frequently, or when an indication is received that auser may have a new device in the house. Collecting data over longperiods of time may generally allow for the improvement of bothhouse-independent and house-specific models, and periodically providingthese models to users may improve performance.

When power monitor 120 is first installed it may not have any models ormay only have generic models that apply to classes of devices. Forexample, the initial models may include models that apply generally to adishwasher, an oven, a motor, a pump, and a heating element. As more islearned about devices in a user's house, more specific models may betransmitted to a user's power monitor. For example, if it is learnedthat the user has a Kenmore version 1000 dishwasher, then modelsspecific to a Kenmore version 1000 dishwasher pump and a Kenmore version1000 dishwasher motor may be transmitted to the user's power monitor120. Further, as time goes on, the electrical properties of knowndevices may drift as parts wear or evolve. Accordingly, thehouse-specific models for individual devices may be updated periodicallyso that house-specific models continue to match the devices as theproperties of the devices drift over time.

Electrical event model updater 820 may create house-specific electricalevent models. Houses may have different electrical characteristicsincluding the noise levels and types of noise in electrical signals.Usage data received from a house may be used to create a house-specificelectrical event model that is more reliable in detecting electricalevents.

Transition model updater 830 may create house-specific transitionmodels. Two identical devices (in terms of manufacturer and version) maybehave differently in different houses. The differences may be causedby, for example, variances in manufacturing (e.g., a capacitor may havea slightly higher capacitance in one device than another device), thespecific electrical configuration of a home (e.g., quality of wiring andelectrical interference from other devices), and the age of a device(e.g., older parts may have different electrical characteristics).Because two identical devices may have different electrical properties,better transition models can be created by collecting usage data that isspecific to a device. A house-specific transition model may be createdusing the same techniques as house-independent models, but withdifferent data. House-independent models may be created with data frommany houses, but house-specific models may use a greater amount of datafrom the house it is being created for.

Any appropriate techniques may be used to create a house-specifictransition model. For example, a first model may be created with ageneral data set, a second model can be created with house specificdata, and the two models may be interpolated to create a house specificmodel. The weights of each model in the interpolation may depend, forexample, on the amount of house specific data that is available.

Device model updater 840 may create house-specific device models. Wheredevice models are represented using directed graphs, such as the devicemodel of FIG. 4, parameters of the directed graph may be adapted tomatch a specific device. For example, a directed graph for a dishwashermay have different paths for a normal wash and a pot scrubbing wash. Ifone user generally uses the pot scrubbing wash and not the normal wash,then path probabilities may be increased for the pot scrubbing wash tomatch the expected behavior of the user. Other parameters that may beadjusted include the expected duration and expected power usagecorresponding to different states of the directed graph.

Wattage model updater 850 may create house-specific wattage models. Twoidentical devices may behave differently in different houses. Usage dataspecific to a house may be used to create a house-specific wattage modelusing the same techniques as for creating house-independent modelsdiscussed above.

Prior model updater 860 may create house-specific prior models.House-specific prior models may incorporate information specific to ahouse, such as location (which indicates daylight hours andtemperature), number of people, number of floors, number of rooms, andtype of building (single-family house, condo, apartment building etc.).This information may be provided by a user or automatically learned fromhistorical usage data. Usage data from a house may also be used tobetter predict when individual devices are likely to be used. Forexample, a user's morning routine in getting ready to go to work(turning on the bedroom light, turning on the bathroom light, turning onthe water in the shower, etc.) may be incorporated into a prior model toallow a power monitor to more accurately recognize these device events.

Model validator 865 may be used to evaluate the performance of anyupdated or adapted models before they are sent to individual powermonitor devices. New models may only be sent where the new modelsperform better than old models. Model validator 865 may evaluate theupdated or adapted models by running them against stored usage data(which may be house specific or house independent). Where the storedusage data is labeled, error metrics can be determined for both newmodels and old models, and the improved performance of the new modelsmay be verified before being sent to individual power monitor devices.

Applications

The above techniques for informing users about home device usageprovides many benefits to users and homeowners. For example, users canbenefit by increasing energy efficiency, receiving warnings aboutdevices that are not functioning correctly, and monitoring device eventsin the home from afar.

Understanding energy usage of individual devices in the home providesnumerous opportunities for improving energy efficiency. Expert systemsmay be created that receive energy usage information for a home andautomatically provide suggestions to users for actions they can take toimprove energy efficiency. In some implementations, the expert systemsmay compare the energy usage of the devices currently in the home withreplacement devices that are available and compare the cost of devicereplacement with the reduced energy costs provided by the replacementdevice. For example, an expert system may determine that the mosteffective action a user can take is to replace a ten-year oldrefrigerator with a new model and inform the user that new refrigeratorwill pay for itself in energy savings in 18 months. The expert systemsmay further be improved by receiving feedback about which suggestionsusers are actually implemented by users. With this additional feedback,an expert system can favor recommendations that are more likely to beimplemented by users. Additionally, users may be informed about the bestdeals for purchasing devices and directed to a local or online merchant.

In addition, by collecting data about many different versions ofdevices, information about actual energy usage and efficiency of devicesmay be determined, and this information may be more accurate thaninformation provided by manufacturers. Versions of devices may then beranked according to efficiency and this information provided to the userto help the user select a new device.

In addition to informing users about their own energy usage, they mayalso be informed about how their energy usage compares to specificpeople (e.g., friends and family) or other people in similar situations(e.g., people in the same geographical location with similar sizedhouses). By learning about their own energy usage with respect toothers, users may be more motivated to reduce their energy usage. Insome implementations, time-specific reminders could be sent to users.For example, in July, users can be reminded or informed that they usedmore energy than their friends and family, and providing recommendationsfor reducing air conditioner usage.

In some implementations, social networks and social networkingapplications may be used. Users may post on social networks informationabout their energy usage, how energy usage has changed over time, andthe effectiveness of specific changes in reducing energy usage. Theuser's posts may be backed by specific data obtained from a powermonitor. Energy usage may be promoted by creating games based on energyusage, competitions, and featuring creative approaches for savingenergy. Information about how a variety of users have taken actions toreduce energy usage and the resultant energy savings may also be used toimprove, for example, the expert system for providing recommendationsfor saving energy.

Understanding electrical energy usage of devices in the home may alsoallow users to conserve other resources. For example, understanding theelectrical usage of a furnace, boiler, dryer, stove, or hot water heatermay allow the determination of water, oil, or gas used by these devices.For example, where the manufacturer and version of these devices may bedetermined by their electrical properties, models may be created thatdetermine the amount of water, gas, or oil used by these devices inaddition to their electrical usage. Other data may be used determine theamount of water, gas, or oil used by devices, including but not limitedto information obtained from water, gas, or oil bills (e.g., manuallyentered by a user or obtained automatically) or usage informationobtained from other sources, such as the utility company (e.g., usingweb scraping techniques, using an API provided by a utility company toobtain information from a server of the utility company, or obtaininginformation from a smart meter for water, gas, or oil).

The techniques described herein for disaggregating electrical signalsmay further be applied to disaggregating other types of signals. Sensorsmay be placed on water, oil, and gas inlets. By processing a gas signal,for example, the gas usage by a stove, furnace, and hot water heater maybe determined by using models and search techniques described above.Disaggregation of water, oil, and gas signals may also be performed inconjunction with disaggregation of electrical signals as jointdisaggregation may perform better than individual disaggregations.

In some implementations, power monitor 120 may be able to interact withand/or control other devices in the house. An increasing number ofdevices in a house are connected to a network. Where these connecteddevices have an API, and power monitor 120 can connect to them, powermonitor 120 can control them for increased energy savings. For example,using expert systems, energy saving strategies may be determined, andpower monitor 120 can control a thermostat, lights, or other devices todirectly implement these energy saving strategies.

Understanding the operation of specific devices in the home may alsoallow for the automatic identification of devices that need maintenance,are broken, or are likely to break down in the near future. Ascomponents of devices wear out or break, the electrical properties ofthe components may change. In some implementations, these changes may bedetected using models, such as transition models. For example, as thepump of a dishwasher deteriorates, the electrical properties may changein a predictable way. In some implementations, transition models may becreated for the various stages in the lifetime of the dishwasher pump.As the dishwasher ages, a transition models for an old and worn out pumpmay provide a better match than the transition model for a new pump.When this happens, a notification may be sent to the user that the pumpis likely to fail in the near future. A user may additionally beinformed that routine maintenance should be performed to improve theenergy efficiency of a device (e.g., that a furnace needs to be cleanedor a filter needs to be replaced on an HVAC system), that routinemaintenance should be performed to prevent a device from breaking down,or that the dishwasher isn't working because the water pump broke.

In some implementations, fault models may be specifically created todetect known types of faults for devices or to detect known precursorsfor known types of faults. For specific devices or for classes ofdevices, the top faults or failure modes may be determined (e.g., byspeaking to experts or collecting data). For each of these potentialfaults, electrical signals and events may be collected for the timeperiod leading up to the fault, during the fault, and after the fault.This data may then be used to create one or models for fault detection.In some implementations, one model may indicate that a fault is likelyto happen soon, another model may indicate that a fault is happeningnow, and another model may indicate that the fault has already happened.For example, a dishwasher may have known faults or failure modes, suchas a capacitor in a motor failing or a bearing in a motor failing.Models can be created for these faults and applied by power monitor 120to detect them and inform the user of likely reasons why the dishwasheris not working.

Understanding the operation of devices in the home also allows users tomonitor activity in the home for informational purposes, including whenthey are away, such as at work or on vacation. Users can be providedwith periodic reports (e.g., weekly) regarding uses of various devices.For example, a user may be informed that the television was watched for30 hours in the past week, but the treadmill was only used for 20minutes. For monitoring purposes, certain activities in the house mayhave repetitive patterns and models may be constructed to processsequences of device events to determine what activities are occurring.For example, when a house cleaner comes to clean the house, the sequenceof device usage may be similar on each occasion. When this pattern isdetected, a notification may be sent to inform a user when the housecleaners arrive and depart. In another example, use of the television bychildren may be detected and recorded, and the parents can be sent anotification indicating how much television the children watched eachday. Notifications may be sent out for other conditions that may bedangerous or undesirable. For example, a notification may be sent outthat the oven was left on or that the garage door was not closed aftergoing to work. For senior citizens, patterns may be detectedcorresponding to emergencies or situations where help is needed, andnotifications may be sent out to friends and family to provideassistance. When away on vacation, patterns may be detected thatindicate that someone may be breaking into your home. Thesenotifications (and any other notifications referred to herein) may besent to any device, including but not limited to user device 150, andmay be sent using email, text message, an application notification, orany other communication medium.

Any appropriate classification techniques may be used for detectingpatterns in a home that correspond to specific situations. Classifiersmay include, but are not limited to, neural networks, self-organizingmaps, support vector machines, decision trees, linear and non-linearregression, random forests, and Gaussian mixture models. Theseclassifiers may be trained with labeled data. For example, a user mayindicate days and times house cleaners came, and these sequences ofdevice events may be retrieved and used to train a house cleanerdetection classifier. Such models may be house specific or houseindependent.

In some implementations, information obtained from power monitors may beshared with third parties (either anonymized or with the users'permission). For example, electric utilities may benefit fromunderstanding the types of power consumed by users. Where many users areinstalling a new type of device (e.g., a dishwasher) that has differentload properties (e.g., inductive instead of resistive), then theelectric utility may be able to improve its services.

Illustrative Processes

In some implementations, information about electricity usage of devicesmay be transmitted to a user device as described in the followingclauses and illustrated by FIG. 11.

1. A method for providing information about a plurality of devices in abuilding, the method comprising:

accepting from a user device a first network connection;

receiving an identifier from the user device;

retrieving first information from a data store using the identifier,wherein the first information comprises historical information about afirst device and a second device;

transmitting the first information to the user device;

receiving second information from a power monitoring device, wherein thesecond information comprises real-time information about powerconsumption of a third device at a first time and about powerconsumption of a fourth device at the first time; and

transmitting the second information to the user device.

2. The method of clause 1, further comprising:

using at least one of the first information and the second informationto determine that a device needs maintenance or that a part of thedevice needs to be replaced;

transmit information to the user device indicating that the device needsmaintenance or that the part of the device needs to be replaced.

3. The method of clause 1, further comprising:

using at least one of the first information and the second informationto determine a recommendation for conserving energy;

transmit the recommendation to the user device.

4. The method of clause 3, wherein using at least one of the firstinformation and the second information to determine a recommendation forconserving energy comprises using an expert system.

5. The method of clause 1, further comprising:

accepting from the user device a second network connection;

wherein transmitting the first information to the user device comprisestransmitting the first information using the first network connection;and

wherein transmitting the second information to the user device comprisestransmitting the second information using the second network connection.

6. The method of clause 1, wherein the first information comprisesinformation about a state change of the first device.

7. The method of clause 1, wherein transmitting the second informationto the user device comprises transmitting the information withoutsignificant delay from the first time.

8. A system for providing information about a plurality of devices, thesystem comprising:

at least one server computer comprising at least one processor and atleast one memory, the at least one server computer configured to:

-   -   accept from a first client device a first network connection;    -   receive an identifier from the first client device;    -   retrieve first information from a data store using the        identifier, wherein the first information comprises historical        information about a first device;    -   transmit the first information to the first client device;    -   receive second information from a second client device, wherein        the second information comprises real-time information about        power consumption of a second device at a first time; and    -   transmit the second information to the first client device.        9. The system of clause 8, wherein the at least one server        computer is further configured to:

use at least one of the first information and the second information todetermine information about a comparison between power usage by a firstbuilding and by a second building or between the first building over afirst time period and the first building over a second time period;

transmit the information about the comparison to the user device.

10. The system of clause 8, wherein the at least one server computer isfurther configured to:

use at least one of the first information and the second information todetermine the occurrence of an event in a building comprising theplurality of devices;

transmit the information about the event.

11. The system of clause 10, wherein the at least one server computer isfurther configured to transmit the information about the event as anotification to a device.

12. The system of clause 8, wherein the at least one server computercomprises a first server computer and a second server computer, thefirst information is transmitted by the first sever computer, and thesecond information is transmitted by the second server computer.13. The system of clause 8, wherein at least a portion of the firstinformation was previously received from the second client device.14. The system of clause 8, wherein the second information istransmitted to the first client device without significant delay fromthe first time.15. A non-transitory computer-readable medium comprising computerexecutable instructions that, when executed, cause at least oneprocessor to perform actions comprising:

establishing a first network connection using a network interface;

establishing a second network connection using the network interface;

receiving first information via the first network connection, whereinthe first information comprises historical information about a firstdevice; and

receiving second information via the second network connection, whereinthe second information comprises real-time information about powerconsumption of a second device at a first time.

16. The computer-readable medium of clause 15, wherein the instructionsfurther cause the at least one processer to perform actions comprisingpresenting the first information and the second information to a user.

17. The computer-readable medium of clause 15, wherein the first networkconnection is with a first server computer and the second networkconnection is with a second server computer.

18. The computer-readable medium of clause 15, wherein the firstinformation comprises information about a state change of the firstdevice.

19. The computer-readable medium of clause 15, wherein the secondinformation is received without significant delay from the first time.

20. The computer-readable medium of clause 15, wherein the instructionsfurther cause the at least one processer to perform actions comprising:

receiving a recommendation for conserving energy; and

presenting the recommendation to a user.

21. The computer-readable medium of clause 15, wherein the instructionsfurther cause the at least one processer to perform actions comprising:

receiving third information via the first network connection, whereinthe third information comprises historical information about the seconddevice; and

receiving fourth information via the second network connection, whereinfourth information comprises real-time information about powerconsumption of the first device at the first time.

FIG. 11 is a flowchart showing an example implementation for providinghistorical and real-time information about devices. Note that theordering of the steps of FIG. 11 (as well as the steps for the otherflowcharts described below) are exemplary and that other orders arepossible. At step 1110, a network connection is created between a serverand a first client device. The server may be, for example, server 140,API server 610, or monitor bridge 620. The first client device may be,for example, user device 150. The network connection may be initiated byeither the server or first client device. The first client device maytransmit an identifier to the server, such as a user ID, a house ID, ora device ID. At step 1120, the server obtains historical informationabout devices, such as devices in a house or building associated withthe first client device. The historical information may be retrievedfrom a database using the identifier. The historical information mayinclude any information about past operation of devices, for example,historical power usage by a building or individual devices in thebuilding, device events of devices in the building, or any otherinformation that may be derived from the processed electrical signals asdescribed above. In some implementations, other information may betransmitted to the first client device, as described above, such asrecommendations for conserving power, maintenance of devices, eventsoccurring in the building, and comparisons of power usage. A comparisonof power usage may be between two buildings (e.g., two homes) usinginformation from a first power monitor in a first building andinformation from a second power monitor in a second building. Acomparison may also be for a single building over two time periods, suchas a first month and a second month. At step 1130, the historicalinformation is transmitted to the first client device. The first clientdevice may present the historical information to a user. At step 1140,the server or another server (such as monitor bridge 620) may receiveinformation about real-time power consumption of devices from a secondclient device. The second client device may be power monitor 120. Atstep 1150, the real-time information about power consumption of devicesis transmitted to the first client device. This transmission may beperformed using the same network connection as step 1130 or a differentnetwork connection. The historical information and the real-timeinformation may be regarding the same set of devices, two completelydifferent sets of devices, or overlapping sets of devices. For example,the historical information may be about a refrigerator and a furnace,and the real-time information may be about a light bulb and therefrigerator. The network connection may be a continuous connection inthat it is maintained even when not in use.

In some implementations, information about electricity usage of devicesmay be presented to a user as described in the following clauses and asillustrated in FIG. 12.

1. A method for presenting on a user device information aboutelectricity usage of a plurality of devices, the method comprising:

receiving first power consumption information corresponding to powerconsumption of a first device and second power consumption informationcorresponding to power consumption of a second device, wherein the firstpower consumption information and the second power consumptioninformation correspond to power consumption at substantially a firsttime;

presenting the first power information and second power information on afirst portion of a display of the user device using a first graphicalrepresentation corresponding to the first power consumption informationand a second graphical representation corresponding to the second powerconsumption information;

receiving first device event information corresponding to a change indevice state for a third device and second device event informationcorresponding to a change in device state for a fourth device; and

presenting the first device event information and the second deviceevent information on a second portion of the display of the device.

2. The method of clause 1, wherein the first graphical representationincludes a name of the first device, the first graphical representationincludes a circle, and an area of the circle corresponds to the firstpower information.

3. The method of clause 1, wherein the first power consumptioninformation corresponds to an amount of energy consumed by the firstdevice during a first time interval, a peak power consumption during thefirst time interval, or an average power consumption during the firsttime interval.4. The method of clause 1, further comprising:

receiving third power consumption information corresponding to powerconsumption of the first device and fourth power consumption informationcorresponding to power consumption of the second device, wherein thethird power consumption information and the fourth power consumptioninformation correspond to power consumption at substantially a secondtime;

modifying the first graphical representation to correspond to the thirdpower consumption information; and

modifying the second graphical representation to correspond to thefourth power consumption information.

5. The method of clause 1, wherein the first power consumptioninformation is received without significant delay from the first time.

6. The method of clause 1, wherein presenting the first device eventinformation and the second device event information comprises presentingthe first device event information and the second device eventinformation in chronological order.

7. The method of clause 1, wherein the first device event informationcomprises a first time and a name of the third device.

8. The method of clause 1, wherein the first device event informationcomprises at least one of an indication that the first device was turnedon, an indication that the first device was turned off, a number oftimes the first device was used over a first time period, an indicationthat the first device has completed a task, an amount of time the firstdevice has been on, a suggested action for a user to conserve energywith the first device, an indication that the first device needsmaintenance, an indication that the first device should be replaced, oran indication that a component of the first device is broken.9. The method of clause 1, further comprising:

receiving third power consumption information corresponding to powerconsumption of the third device and fourth power consumption informationcorresponding to power consumption of the fourth device, wherein thethird power consumption information and the fourth power consumptioninformation correspond to power consumption at substantially a firsttime; and

receiving third device event information corresponding to a change indevice state for the first device and fourth device event informationcorresponding to a change in device state for the second device.

10. A user device for presenting information about electricity usage ofa plurality of devices, the device comprising:

a network interface;

a display;

at least one processor;

at least one memory storing processor-executable instructions that, whenexecuted by the at least one processor, cause the at least one processorto:

-   -   receive, via the network interface, first power consumption        information corresponding to power consumption of a first        device, wherein the first power consumption information        corresponds to power consumption at substantially a first time;    -   present the first power consumption information on the display        using a first graphical representation corresponding to the        first power consumption information;    -   receive, via the network interface, second power consumption        information corresponding to power consumption of the first        device, wherein the second power consumption information        corresponds to power consumption at substantially a second time;    -   modify the first graphical representation to correspond to the        second power consumption information.        11. The user device of clause 10, wherein the first power        consumption information and the second power information are        received without significant delay.        12. The user device of clause 10, wherein the first power        consumption information corresponds to a first time period of an        electrical signal, the second power consumption information        corresponds to a second time period of the electrical signal,        and wherein the second time period immediately follows the first        time period.        13. The user device of clause 10, wherein the first power        consumption information is presented within one second of the        first time.        14. The user device of clause 10, wherein the first graphical        representation includes a circle, and wherein the area of the        circle corresponds to the first power consumption information.        15. The user device of clause 10, wherein the at least one        memory storing processor-executable instructions that, when        executed by the at least one processor, further cause the at        least one processor to:

receive, via the network interface, a first number of watts consumed bya plurality of devices at substantially the first time;

present the first number of watts on the display;

receive, via the network interface, a second number of watts consumed bythe plurality of devices at substantially the second time; and

present the second number of watts on the display.

16. A non-transitory computer-readable medium comprising computerexecutable instructions that, when executed, cause one or moreprocessors to perform actions comprising:

receiving first power consumption information corresponding to powerconsumption of a first device, wherein the first power consumptioninformation corresponds to power consumption at substantially a firsttime;

presenting the first power consumption information on a display using afirst graphical representation corresponding to the first powerconsumption information;

receiving a first user input; and

presenting, in response to receiving the first user input, firsthistorical power consumption information corresponding to a first timeperiod and second historical power consumption information correspondingto a second time period.

17. The non-transitory computer-readable medium of clause 16, whereinthe first user input comprises requesting historical power consumptioninformation about the first device or a plurality of devices.

18. The non-transitory computer-readable medium of clause 16, whereinpresenting first historical power consumption information correspondingto a first time period and second historical power consumptioninformation corresponding to a second time period comprises presentingat least one of a bar chart or a line chart.19. The non-transitory computer-readable medium of clause 16, whereinthe first time period corresponds to a day, a week, a month, or a year.20. The non-transitory computer-readable medium of clause 16, theactions further comprising:

receiving second power consumption information corresponding to powerconsumption of the first device, wherein the second power consumptioninformation corresponds to power consumption at substantially a secondtime;

modifying the first graphical representation to correspond to the secondpower consumption information.

21. The non-transitory computer-readable medium of clause 16, theactions further comprising:

receiving a second user input; and

presenting, in response to receiving the second user input, thirdhistorical power consumption information corresponding to a proportionof power used by a first device and fourth historical power consumptioninformation corresponding to a proportion of power used by a seconddevice.

FIG. 12 is a flowchart showing an example implementation of presentinghistorical and real-time information about devices to a user, which maybe performed, for example, by user device 150. At step 1210, real-timeinformation about power consumption of a plurality of devices isreceived. For example, this information may be received from powermonitor 120 via monitor bridge 620. The real-time information may bereceived at regular intervals, such as every second or every electricalcycle and may correspond to a number of watts consumed over a timeinterval. The real-time information about power consumption maycorrespond substantially to a first time. For example, the informationmay relate to energy used over a time period, average power over a timeperiod, or peak power over a time period. The time of the informationmay correspond approximately (subject to small errors and uncertaintiesin timing) to the beginning, middle, or end of the time period, or to arange of time. At step 1220, graphical representations are displayed toindicate to a user the power consumption information. For example,graphical representations, such as circles, may be displayed, whereineach circle corresponds to a device, and the circles may be updated inreal time. At step 1230, historical information about device events isreceived. The devices corresponding to the device events may be the samedevices or some of the same devices as step 1210 or may be differentdevices, and device events may include any information described above.At step 1240, the information about device events is presented on adisplay, such as by presenting a chronological list of device events. Atstep 1250, a user may provide a user input, such as touching/clicking ona graphical element or device event, to obtain historical informationabout power consumption. For example, a bar chart may be presentedindicating power consumption of one or more devices over a time periodor a pie chart may be presented indicating relative power consumption ofone or more devices.

In some implementations, information about electricity usage of devicesmay be transmitted to a user device using a network architecture asdescribed in the following clauses and illustrated in FIG. 13.

1. A method for providing information about a plurality of devices in abuilding, the method performed by a power monitoring device in thebuilding and comprising:

establishing a first network connection between the power monitoringdevice and a first server computer, wherein the first network connectionis maintained when not in use;

determining that a first device event occurred using an electricalsignal, wherein the electrical signal comprises at least one of avoltage signal, a current signal, a power signal, or a reactive powersignal;

transmitting information about the first device event to a second servercomputer using a second network connection, wherein the second networkconnection is closed after transmitting the information about the firstdevice event;

receiving a request, from the first server via the first networkconnection, to provide real-time information about power consumption ofthe plurality of devices in the building;

determining information about power consumption of the plurality ofdevices at a first time;

transmitting, to the first server via the first network connection, theinformation about power consumption of the plurality of devices;

receiving a request, from the first server via the first networkconnection, to stop providing real-time information about powerconsumption of the plurality devices in the building; and

maintaining the first network connection with the first server.

2. The method of clause 1, wherein the first device event corresponds toa device of the plurality of devices transitioning from an on state toan off state or transitioning from an off state to an on state.

3. The method of clause 1, wherein the electrical signal is obtainedusing at least one of a voltage sensor or a current sensor.

4. The method of clause 1, wherein the information about powerconsumption of the plurality of devices at a first time comprises anamount of energy consumed by the first device over a time period.

5. The method of clause 1, further comprising:

receiving a request from the first server computer to disconnect andconnect to a third server;

disconnecting the first connection to the first server; and

establishing a third network connection between the power monitoringdevice and the third server computer, wherein the third networkconnection is maintained when not in use.

6. The method of clause 1, wherein transmitting information about powerconsumption of the plurality of devices comprises transmitting theinformation without significant delay from the first time.

7. The method of clause 1, wherein:

determining that a first device event occurred comprises processingelectrical events from the electrical signal using a first processingmode; and

determining information about power consumption of the plurality ofdevices at a first time comprises processing electrical events from theelectrical signal using a second processing mode.

8. A system for providing information about a plurality of devices in abuilding, the system comprising:

a first server computer comprising at least one processor and at leastone memory, the first server computer configured to:

-   -   accept, from a first client computer, a first network        connection, wherein the first network connection is maintained        when not in use,    -   accept, from a second client computer, a second network        connection;    -   transmit, to the first client computer, a request to provide        real-time information about power consumption of the plurality        of devices in the building,    -   receive, from the first client computer, first information,        where in the first information corresponds to power consumption        of the plurality of devices at a first time,    -   transmit, to a second client computer, the first information,    -   transmit, to the first client computer, a request to stop        providing real-time information,    -   close the second network connection, and    -   maintain the first network connection.        9. The system of clause 8, further comprising a second server        computer comprising at least one processor and at least one        memory, the second server computer configured to:

accept, from the first client computer, a third network connection,

receive, from the first client computer, second information, and

close the third network connection.

10. The system of clause 8, wherein the first server computer is furtherconfigured to modify the first information before transmitting to thesecond client computer.

11. The system of clause 8, wherein the first client computer comprisesa power monitor that receives electrical signals from an electricalpanel, and the second client computer is a user device.

12. The system of clause 8, further comprising a third server computer,wherein the first server computer is further configured to transmit, tothe first client computer, an instruction to disconnect from the firstserver computer and connect to the third server computer.13. The system of clause 8, wherein the first server is furtherconfigured to transmit, to the second client computer, the firstinformation without significant delay from the first time.14. A non-transitory computer-readable medium comprising computerexecutable instructions that, when executed, cause at least oneprocessor to perform actions comprising:

establishing a first network connection between the device and a firstserver computer, wherein the first network connection is maintained whennot in use;

receiving a request, from the first server via the first networkconnection, to provide real-time information about power consumption ofthe plurality of devices in the building;

determining information about power consumption of the plurality ofdevices at a first time;

transmitting, to the first server via the first network connection, theinformation about power consumption of the plurality of devices;

receiving a request, from the first server via the first networkconnection, to stop providing real-time information about powerconsumption of the plurality of devices in the building; and

maintain the first network connection with the first server.

15. The computer-readable medium of clause 14, wherein theprocessor-executable instructions further cause the at least oneprocessor to perform actions comprising:

determining that a first device event occurred using an electricalsignal;

establishing a second network connection with a second server computer;

transmitting information about the first device event to the secondserver computer using the second network connection; and

closing the second network connection.

16. The computer-readable medium of clause 14, wherein the electricalsignal is obtained using at least one of a voltage sensor or a currentsensor.

17. The computer-readable medium of clause 14, wherein the informationabout power consumption of the plurality of devices at a first timecomprises an amount of energy consumed by the first device over a timeperiod.

18. The computer-readable medium of clause 14, wherein theprocessor-executable instructions further cause the at least oneprocessor to perform actions comprising:

receiving a request from the first server computer to disconnect andconnect to a third server computer;

disconnecting the first network connection to the first server; and

establishing a third network connection between the device and the thirdserver computer, wherein the third network connection is maintained whennot in use.

19. The computer-readable medium of clause 14, wherein theprocessor-executable instructions cause the at least one processor toperform actions comprising transmitting information about powerconsumption of the plurality of devices without significant delay fromthe first time.20. The computer-readable medium of clause 15, wherein theprocessor-executable instructions further cause the at least oneprocessor to perform actions comprising:

determining that a first device event occurred comprises processingelectrical events from an electrical signal using a first processingmode; and

determining information about power consumption of the plurality ofdevices at a first time comprises processing electrical events from theelectrical signal using a second processing mode.

FIG. 13 is a flowchart showing an example implementation of anarchitecture for providing real-time information about devices. At step1310, a network connection is established between a client device andserver computer. For example, between power monitor 120 and server 140or monitor bridge 620. The first network connection may be a continuousnetwork connection in that it is maintained when not in use. At step1320, a second network connection is established between a client deviceand a second server computer. For example, between power monitor 120 andserver 140 or API server 610. At step 1330, the client device maydetermine information about device events, such as any of the deviceevent information discussed above, and transmit this information to thesecond server using the second network connection. As described above,the device event information may be sent periodically, and the secondnetwork connection may be terminated after transmitting the device eventinformation. At step 1340, the first server may transmit a request tothe client device to provide real-time information, such as real-timeinformation about power consumption by a plurality of devices orreal-time information about device events. At step 1350, the clientdevice may transmit the requested real-time information to the firstserver. At step 1360, the first server may transmit a request to theclient device to stop transmitting real-time information. At step 1370,the client device may stop transmitting real-time information, butmaintain the first network connection with the first server as describedabove.

In some implementations, device events may be determined as described inthe following clauses and illustrated in FIG. 14.

1. A method for determining state changes of devices in a building, themethod performed by a monitoring device in the building, the methodcomprising:

receiving an electrical signal, wherein the electrical signalcorresponds to electrical usage of a plurality of devices, and whereinthe electrical signal comprises at least one of voltage signal, acurrent signal, a power signal, or a reactive power signal;

identifying an electrical event in the electrical signal, wherein theelectrical event corresponds to a first time;

computing a first feature using a first portion of the electricalsignal, wherein the first portion comprises the first time;

computing a second feature using a second portion of the electricalsignal, wherein the second portion comprises the first time and whereinan end time of the second portion is later than an end time of the firstportion;

performing first processing comprising:

-   -   computing a first score using the first feature and a model,        wherein the model corresponds to one or more devices and a state        change of the one or more devices and wherein computing the        first score does not use the second feature, and    -   selecting, using the first score, a first device and a first        state change; and

performing second processing comprising:

-   -   computing a second score using the first feature, the second        feature, and the model, and    -   selecting, using the second score, (i) the first device and the        first state change, or (ii) a second device and a second state        change.        2. The method of clause 1, wherein identifying the electrical        event in the electrical signal comprises computing a first value        for a first window of the electrical signal prior to the first        time, computing a second value for a second window of the        electrical signal after the first time, and comparing the first        value to the second value.        3. The method of clause 1, wherein the first feature is computed        before the end time of the second portion of the electrical        signal.        4. The method of clause 1, wherein:

the first processing further comprises transmitting, to a first servercomputer, first information about the first device and the first statechange; and

the second processing further comprises transmitting, to a second servercomputer, second information about (i) the first device and the firststate change or (ii) the second device and the second state change.

5. The method of clause 1, wherein the first processing furthercomprises computing the first score using a transition model thatcorresponds to a state change of an element of the first device and adirected graph describing a plurality of state changes of the firstdevice.6. The method of clause 1, wherein the first processing furthercomprises selecting the first device and the first state change bygenerating a directed graph with a plurality of nodes, wherein a firstnode of the graph corresponds to the first device and the first statechange.7. The method of clause 4, wherein the first processing furthercomprises transmitting the first information to the first server withoutsignificant delay from the first time.8. A monitoring device for determining state changes of devices in abuilding, the device comprising:

at least one processor;

at least one memory storing processor-executable instructions that, whenexecuted by the at least one processor, cause the at least one processorto:

-   -   receive an electrical signal, wherein the electrical signal        corresponds to electrical usage of a plurality of devices;    -   identify an electrical event in the electrical signal, wherein        the electrical event corresponds to a first time;    -   compute a first feature using a first portion of the electrical        signal, wherein the first portion comprises the first time;    -   compute a second feature using a second portion of the        electrical signal, wherein the second portion comprises the        first time and wherein an end time of the second portion is        later than an end time of the first portion;    -   perform first processing comprising:        -   computing a first score using the first feature, wherein            computing the first score does not use the second feature,            and        -   selecting, using the first score, a first device and a first            state change; and    -   perform second processing comprising:        -   computing a second score using the first feature and the            second feature, and        -   selecting, using the second score, (i) the first device and            the first state change, or (ii) a second device and a second            state change.            9. The monitoring device of clause 8, wherein the at least            one processor identifies the electrical event in the            electrical signal by computing a first value for a first            window of the electrical signal prior to the first time,            computing a second value for a second window of the            electrical signal after the first time, and comparing the            first value to the second value.            10. The monitoring device of clause 8, wherein the first            feature is computed before the end time of the second            portion of the electrical signal.            11. The monitoring device of clause 8, wherein:

the first processing further comprises transmitting, to a first servercomputer, first information about the first device and the first statechange; and

the second processing further comprises transmitting, to a second servercomputer, second information about (i) the first device and the firststate change or (ii) the second device and the second state change.

12. The monitoring device of clause 8, wherein the first processingfurther comprises computing the first score using a transition modelthat corresponds to a state change of an element of the first device anda directed graph describing a plurality of state changes of the firstdevice.13. The monitoring device of clause 8, wherein the first processingfurther comprises selecting the first device and the first state changeby generating a directed graph with a plurality of nodes, wherein afirst node of the graph corresponds to the first device and the firststate change.14. The monitoring device of clause 11, wherein the first processingfurther comprises transmitting the first information to the first serverwithout significant delay from the first time.15. A non-transitory computer-readable medium comprising computerexecutable instructions that, when executed, cause at least oneprocessor to perform actions comprising:

receiving an electrical signal, wherein the electrical signalcorresponds to electrical usage of a plurality of devices;

identifying an electrical event in the electrical signal, wherein theelectrical event corresponds to a first time;

computing a first feature using a first portion of the electricalsignal, wherein the first portion comprises the first time;

computing a second feature using a second portion of the electricalsignal, wherein the second portion comprises the first time and whereinan end time of the second portion is later than an end time of the firstportion;

performing first processing comprising:

-   -   computing a first score using the first feature, wherein        computing the first score does not use the second feature, and    -   selecting, using the first score, a first device and a first        state change; and

performing second processing comprising:

-   -   computing a second score using the first feature and the second        feature, and    -   selecting, using the second score, (i) the first device and the        first state change, or (ii) a second device and a second state        change.        16. The computer-readable medium of clause 15, wherein        identifying the electrical event in the electrical signal        comprises computing a first value for a first window of the        electrical signal prior to the first time, computing a second        value for a second window of the electrical signal after the        first time, and comparing the first value to the second value.        17. The computer-readable medium of clause 15, wherein the first        feature is computed before the end time of the second portion of        the electrical signal.        18. The computer-readable medium of clause 15, wherein:

the first processing further comprises transmitting, to a first servercomputer, first information about the first device and the first statechange; and

the second processing further comprises transmitting, to a second servercomputer, second information about (i) the first device and the firststate change or (ii) the second device and the second state change.

19. The computer-readable medium of clause 15, wherein the firstprocessing further comprises computing the first score using atransition model that corresponds to a state change of an element of thefirst device and a directed graph describing a plurality of statechanges of the first device.20. The computer-readable medium of clause 18, wherein the firstprocessing further comprises transmitting the first information to thefirst server without significant delay from the first time.21. The computer-readable medium of claim 18, wherein the firstinformation is used to provide real-time information about the firstdevice to a user and the second information is used to providehistorical information about the first device or the second device tothe user.

FIG. 14 is a flowchart showing an example implementation of determininginformation about device events, which may be performed by a device suchas power monitor 120. At step 1410, an electrical signal is received.For example, the electrical signal may be a power, current, or voltagesignal. At step 1420 an electrical event is identified from theelectrical signal, for example, by using any of the techniques discussedabove. At step 1430, a first feature (or first set of features) iscomputed using a first portion of the electrical signal that includesthe electrical event. At step 1440 a first device and first state changeare selected using the first feature and a model and without using thesecond feature described below. For example, a real-time search processmay be used as described above. At step 1450, a second feature (orsecond set of features) is computed using a second portion of theelectrical signal that includes the electrical event. The second portionof the electrical signal may have an end time that is later than an endtime of the first portion of the electrical signal, and thus it may notbe possible to compute the second feature at the time the first featureis computed (because a needed portion of the electrical signal had notbeen received at that time). At step 1460, a second device and secondstate change are selected using the first feature, the second feature,and a model. For example, a historical search process may be used asdescribed above. Selecting the second device and second state change maybe more accurate than the selection of the first device and first statechange because the second feature may have additional information thatis not present in the first feature. At step 1470, information about thefirst device and first state change and the second device and secondstate change may be sent to a server. In some implementations, theinformation about the first device and first state change may be sent toa first server and the information about the second device and secondstate change may be sent to a second server.

In some implementations, devices may be discovered as described in thefollowing clauses and as illustrated in FIG. 15.

1. A method for determining information about a device, comprising:

obtaining first information about plurality of electrical events,wherein the first information comprises a plurality of features for eachelectrical event;

processing the first information with a first model to generate a firstscore, wherein the first model comprises a first plurality of states,and wherein the first model corresponds to a first class of devices;

processing the first information with a second model to generate asecond score, wherein the second model comprises a second plurality ofstates, and wherein the second model corresponds to a second class ofdevices;

selecting the first model as most likely corresponding to the pluralityof electrical events.

2. The method of clause 1, wherein processing the first information withthe first model comprises:

determining that a first event matches a first state of the firstplurality of states;

determining that a second event does not match any state of the firstplurality of states; and

determining that a third event matches a second state of the firstplurality of states.

3. The method of clause 1, wherein the first information is receivedfrom a client device and the second model is transmitted to the clientdevice.

4. The method of clause 1, wherein processing the first information withthe first model comprises:

generating a graph, wherein each node of the graph corresponds anelectrical event; and

selecting a path from graph.

5. The method of clause 4, further comprising:

identifying a plurality of paths of the graph that correspond to an endstate of the first model;

determining a score for each path of the plurality of paths; and

wherein selecting a path from the graph comprises selecting a path ofthe plurality of paths with a highest score.

6. The method of clause 1, further comprising:

generating second information from the first information by removinginformation corresponding to an electrical event that matches a state ofthe second model;

processing the second information with a third model to generate a thirdscore, wherein the third model comprises a third plurality of states;and

selecting the third model as most likely corresponding to the secondinformation.

7. The method of clause 1, wherein the first model and the second modelare selected based on information provided by a user.

FIG. 15 is a flowchart showing an example implementation of discoveringinformation about devices, which may be performed, for example, byserver 140. At step 1510, first information about a plurality ofelectrical events is obtained. The electrical events may be identifiedby power monitor 120, or may be determined by server 140 usingelectrical signals received from power monitor 120. The firstinformation may include features as described above. At step 1520, thefirst information is processed by a first model (such as a devicediscovery model or a device model as described above) to generate afirst score. The processing of the first information with the firstmodel may use any of the techniques described above, such as generatinga discovery graph using device discovery models. The first model maycorrespond to, for example a class of devices, a class of devices by amanufacturer, or a version of a device by a manufacturer. At step 1530,the first information is also processed by a second model (which mayhave any of the characteristics of the first model) to generate a secondscore. The first information may further be processed by any number ofmodels to generate additional scores. The models used may correspond toall available models or may be selected according to informationprovided by a user. For example, if a user indicates that he or she hasa Kenmore dishwasher, then all models relating to Kenmore dishwashersmay be used. At step 1540, a model is selected. For example, a model maybe selected based on the model that produced a highest score. At step1550, a device model is transmitted to a client device, wherein thedevice model corresponds to the same device or class of devices as theselected model. The device model transmitted to the client device may bethe same as or different from the selected model. For example, theselected model may be better suited to discovering a device and a devicemodel may be better suited for identifying transitions of a device usingelectrical events. The first information may include information aboutmultiple devices, and the above process may be repeated to identifyadditional devices. For example, second information may be created fromthe first information where information about the previously identifieddevice may be removed. This second information may then be processed toidentify a second device.

In some implementations, house-specific models may be generated asdescribed in the following clauses and as illustrated in FIG. 16.

1. A method for updating models for determining information aboutdevices, the method comprising:

transmitting a first model to a client device, wherein the first modelcorresponds to a first class of devices;

receiving first information about a first plurality of electrical eventsfrom the client device, wherein each of the first plurality ofelectrical events is associated with the first model;

selecting a second model using the first information, wherein the secondmodel corresponds to a specific device or a second class of devices; and

transmitting the second model to the client device.

2. The method of clause 1, further comprising:

receiving second information about a second plurality of electricalevents from the client device, wherein each of the second plurality ofelectrical events is associated with the second model;

modifying the second model using the second information; and

transmitting the modified second model to the client device.

3. The method of clause 1, further comprising:

receiving second information about a second plurality of electricalevents from the client device, wherein each of the second plurality ofelectrical events is associated with the second model;

training a third model using the second information; and

transmitting the third model to the client device.

4. The method of clause 3, further comprising:

receiving third information about a third plurality of electrical eventsfrom a second client device, wherein each of the third plurality ofelectrical events is associated with the second model; and

wherein training the third model comprises using the third information.

5. The method of clause 1, wherein selecting the second model comprisesselecting the second model from a plurality of models using a scoregenerated by processing the first information with the second model.

6. The method of clause 1, wherein the first model comprises atransition model or a device model.

7. The method of clause 1, wherein the specific device corresponds to aversion of a device by a manufacturer.

FIG. 16 is a flowchart showing an example implementation of generatinghouse-specific models, which may be performed, for example, by server140. At step 1610, a first model is transmitted to a client device, suchas power monitor 120. The first model may be transmitted to the clientdevice during manufacture so that the model is present when the clientdevice is purchased by a user, or the first model may be transmitted tothe client device after the client device has been purchased andinstalled by the user. The first model may be any of the modelsdiscussed above, including, for example, a transition model or a devicemodel. The first model may correspond to a class of devices becauseinformation is not yet available about devices in the home. At step1620, first information about a first plurality of electrical events isreceived from the client device. The first information may comprise aplurality of features generated from an electrical signal. The firstinformation may be generated during the normal operation of the clientdevice to detect device events in the home or may be specificallygenerated for updating or adapting models. At step 1630, a second modelis generated using the first information and using any of the techniquesdescribed above. For example, the second model may be generated byselecting from a plurality of models using a device discovery process asdescribed above, modifying an existing model (such as the first model),or training a new model using the first information. The second modelmay be specific to a house in that it corresponds to a class of devicesin the house (e.g., Whirlpool dishwashers), a specific version of adevice (e.g., version 1000 Whirlpool dishwasher), or may be adapted tospecific characteristics of the device in the home (e.g., a peculiarityof the motor of the user's dishwasher). At step 1640, the second modelmay be transmitted to the client device. At steps 1650-1670, the sameprocess may be repeated to again generate another house specific model.Steps 1650-1670 may be repeated on an ongoing basis to continuouslyupdate models as new models and/or training data become available.

In some implementations, device events may be determined as described inthe following clauses and as illustrated in FIG. 17.

1. A method for detecting device events, the method comprising:

obtaining a graph comprising a plurality of nodes including a firstnode;

receiving a plurality of features corresponding to an electrical event;

processing the plurality of features with a first model to generate afirst score, wherein the first model corresponds to a state change of afirst device;

processing the plurality of features with a second model to generate asecond score, wherein the second model corresponds to a state change ofa second device;

adding a second node to the graph, wherein the second node correspondsto the state change of the first device and wherein the second nodefollows the first node; and

adding a third node to the graph, wherein the third node corresponds tothe state change of the second device and wherein the third node followsthe first node.

2. The method of clause 1, wherein the first score is generated using atleast one of a transition model, a wattage model, or a prior model.

3. The method of clause 1, further comprising removing the third nodefrom the graph based at least in part on the second score.

4. The method of clause 1, wherein the first node indicates a state foreach of a plurality of devices.

5. The method of clause 1, wherein the first model is selected using afirst device model for the first device, and wherein the first devicemodel indicates allowable state transitions for the first device.

6. The method of clause 1, further comprising:

receiving a second plurality of features corresponding to a secondelectrical event;

processing the second plurality of features with a third model togenerate a third score, wherein the third model corresponds to a statechange of a third device;

processing the plurality of features with a fourth model to generate afourth score, wherein the fourth model corresponds to a state change ofa fourth device;

adding a fourth node to the graph, wherein the fourth node correspondsto the state change of the third device and wherein the fourth nodefollows the second node; and

adding a fifth node to the graph, wherein the fifth node corresponds tothe state change of the fourth device and wherein the fifth node followsthe second node.

7. The method of clause 1, wherein the graph is a directed acyclicgraph.

FIG. 17 is a flowchart showing an example implementation of determiningdevice events, which may be performed, for example, by power monitor120. At step 1710, a graph is obtained comprising a plurality of nodesincluding a first node. The graph may be, for example, a directedacyclic graph or a search graph as described above. Each node of theplurality of nodes may correspond to a possible or hypothesized state ofa plurality of devices. At step 1720, a plurality of features isreceived corresponding to an electrical event. The features may bedetermined using any of the techniques described above. At step 1730,the plurality of features is processed with a first model correspondingto a state change of a first device, such as a light bulb transitioningfrom an off state to an on state. At step 1740, the plurality offeatures is processed with a second model corresponding to a statechange of a second device. Similarly, the plurality of features may beprocessed with additional models corresponding to state changes of otherdevices. The processing of the features with the models may generatescores using any of the techniques described above, for example, usingone or more of a transition score, a wattage score, or a prior score.The processing of the features with the models may correspond to eithera real-time mode or a historical mode as described above. At step 1750,a second node is added to the graph following the first node, whereinthe second node corresponds to the state change of the first device. Atstep 1760, a third node is added to the graph following the first node,wherein the third node corresponds to the state change of the seconddevice. Steps 1720-1760 may be repeated to process features forsubsequent electrical events to add additional nodes to the graph.Further, the nodes of the graph may later be pruned based on scorescorrespond to nodes and/or paths of the graph. For example, nodescorresponding lower scores may be removed to reduce computations.

While only a few embodiments of the present invention have been shownand described, it will be obvious to those skilled in the art that manychanges and modifications may be made thereunto without departing fromthe spirit and scope of the present disclosure as described in thefollowing claims. All patent applications and patents, both foreign anddomestic, and all other publications referenced herein are incorporatedherein in their entireties to the full extent permitted by law.

The methods and systems described herein may be deployed in part or inwhole through a machine that executes computer software, program codes,and/or instructions on a processor. The processor may be part of aserver, cloud server, client, network infrastructure, mobile computingplatform, stationary computing platform, or other computing platform. Aprocessor may be any kind of computational or processing device capableof executing program instructions, codes, binary instructions and thelike. The processor may be or include a signal processor, digitalprocessor, embedded processor, microprocessor or any variant such as aco-processor (math co-processor, graphic co-processor, communicationco-processor and the like) and the like that may directly or indirectlyfacilitate execution of program code or program instructions storedthereon. In addition, the processor may enable execution of multipleprograms, threads, and codes. The threads may be executed simultaneouslyto enhance the performance of the processor and to facilitatesimultaneous operations of the application. By way of implementation,methods, program codes, program instructions and the like describedherein may be implemented in one or more thread. The thread may spawnother threads that may have assigned priorities associated with them;the processor may execute these threads based on priority or any otherorder based on instructions provided in the program code. The processormay include memory that stores methods, codes, instructions and programsas described herein and elsewhere. The processor may access a storagemedium through an interface that may store methods, codes, andinstructions as described herein and elsewhere. The storage mediumassociated with the processor for storing methods, programs, codes,program instructions or other type of instructions capable of beingexecuted by the computing or processing device may include but may notbe limited to one or more of a CD-ROM, DVD, memory, hard disk, flashdrive, RAM, ROM, cache and the like.

A processor may include one or more cores that may enhance speed andperformance of a multiprocessor. In embodiments, the process may be adual core processor, quad core processors, other chip-levelmultiprocessor and the like that combine two or more independent cores(called a die).

The methods and systems described herein may be deployed in part or inwhole through a machine that executes computer software on a server,cloud server, client, firewall, gateway, hub, router, or other suchcomputer and/or networking hardware. The software program may beassociated with a server that may include a file server, print server,domain server, internet server, intranet server and other variants suchas secondary server, host server, distributed server and the like. Theserver may include one or more of memories, processors, computerreadable media, storage media, ports (physical and virtual),communication devices, and interfaces capable of accessing otherservers, clients, machines, and devices through a wired or a wirelessmedium, and the like. The methods, programs or codes as described hereinand elsewhere may be executed by the server. In addition, other devicesrequired for execution of methods as described in this application maybe considered as a part of the infrastructure associated with theserver.

The server may provide an interface to other devices including, withoutlimitation, clients, other servers, printers, database servers, printservers, file servers, communication servers, distributed servers andthe like. Additionally, this coupling and/or connection may facilitateremote execution of program across the network. The networking of someor all of these devices may facilitate parallel processing of a programor method at one or more location without deviating from the scope ofthe disclosure. In addition, any of the devices attached to the serverthrough an interface may include at least one storage medium capable ofstoring methods, programs, code and/or instructions. A centralrepository may provide program instructions to be executed on differentdevices. In this implementation, the remote repository may act as astorage medium for program code, instructions, and programs.

The software program may be associated with a client that may include afile client, print client, domain client, internet client, intranetclient and other variants such as secondary client, host client,distributed client and the like. The client may include one or more ofmemories, processors, computer readable media, storage media, ports(physical and virtual), communication devices, and interfaces capable ofaccessing other clients, servers, machines, and devices through a wiredor a wireless medium, and the like. The methods, programs or codes asdescribed herein and elsewhere may be executed by the client. Inaddition, other devices required for execution of methods as describedin this application may be considered as a part of the infrastructureassociated with the client.

The client may provide an interface to other devices including, withoutlimitation, servers, other clients, printers, database servers, printservers, file servers, communication servers, distributed servers andthe like. Additionally, this coupling and/or connection may facilitateremote execution of program across the network. The networking of someor all of these devices may facilitate parallel processing of a programor method at one or more location without deviating from the scope ofthe disclosure. In addition, any of the devices attached to the clientthrough an interface may include at least one storage medium capable ofstoring methods, programs, applications, code and/or instructions. Acentral repository may provide program instructions to be executed ondifferent devices. In this implementation, the remote repository may actas a storage medium for program code, instructions, and programs.

The methods and systems described herein may be deployed in part or inwhole through network infrastructures. The network infrastructure mayinclude elements such as computing devices, servers, routers, hubs,firewalls, clients, personal computers, communication devices, routingdevices and other active and passive devices, modules and/or componentsas known in the art. The computing and/or non-computing device(s)associated with the network infrastructure may include, apart from othercomponents, a storage medium such as flash memory, buffer, stack, RAM,ROM and the like. The processes, methods, program codes, instructionsdescribed herein and elsewhere may be executed by one or more of thenetwork infrastructural elements.

The methods, program codes, and instructions described herein andelsewhere may be implemented on a cellular network having multiplecells. The cellular network may either be frequency division multipleaccess (FDMA) network or code division multiple access (CDMA) network.The cellular network may include mobile devices, cell sites, basestations, repeaters, antennas, towers, and the like. The cell networkmay be a GSM, GPRS, 3G, EVDO, mesh, or other networks types.

The methods, programs codes, and instructions described herein andelsewhere may be implemented on or through mobile devices. The mobiledevices may include navigation devices, cell phones, mobile phones,mobile personal digital assistants, laptops, palmtops, netbooks, pagers,electronic books readers, music players and the like. These devices mayinclude, apart from other components, a storage medium such as a flashmemory, buffer, RAM, ROM and one or more computing devices. Thecomputing devices associated with mobile devices may be enabled toexecute program codes, methods, and instructions stored thereon.Alternatively, the mobile devices may be configured to executeinstructions in collaboration with other devices. The mobile devices maycommunicate with base stations interfaced with servers and configured toexecute program codes. The mobile devices may communicate on a peer topeer network, mesh network, or other communications network. The programcode may be stored on the storage medium associated with the server andexecuted by a computing device embedded within the server. The basestation may include a computing device and a storage medium. The storagedevice may store program codes and instructions executed by thecomputing devices associated with the base station.

The computer software, program codes, and/or instructions may be storedand/or accessed on machine readable media that may include: computercomponents, devices, and recording media that retain digital data usedfor computing for some interval of time; semiconductor storage known asrandom access memory (RAM); mass storage typically for more permanentstorage, such as optical discs, forms of magnetic storage like harddisks, tapes, drums, cards and other types; processor registers, cachememory, volatile memory, non-volatile memory; optical storage such asCD, DVD; removable media such as flash memory (e.g. USB sticks or keys),floppy disks, magnetic tape, paper tape, punch cards, standalone RAMdisks, Zip drives, removable mass storage, off-line, and the like; othercomputer memory such as dynamic memory, static memory, read/writestorage, mutable storage, read only, random access, sequential access,location addressable, file addressable, content addressable, networkattached storage, storage area network, bar codes, magnetic ink, and thelike.

The methods and systems described herein may transform physical and/oror intangible items from one state to another. The methods and systemsdescribed herein may also transform data representing physical and/orintangible items from one state to another, such as from usage data to anormalized usage dataset.

The elements described and depicted herein, including in flow charts andblock diagrams throughout the figures, imply logical boundaries betweenthe elements. However, according to software or hardware engineeringpractices, the depicted elements and the functions thereof may beimplemented on machines through computer executable media having aprocessor capable of executing program instructions stored thereon as amonolithic software structure, as standalone software modules, or asmodules that employ external routines, code, services, and so forth, orany combination of these, and all such implementations may be within thescope of the present disclosure. Examples of such machines may include,but may not be limited to, personal digital assistants, laptops,personal computers, mobile phones, other handheld computing devices,medical equipment, wired or wireless communication devices, transducers,chips, calculators, satellites, tablet PCs, electronic books, gadgets,electronic devices, devices having artificial intelligence, computingdevices, networking equipments, servers, routers and the like.Furthermore, the elements depicted in the flow chart and block diagramsor any other logical component may be implemented on a machine capableof executing program instructions. Thus, while the foregoing drawingsand descriptions set forth functional aspects of the disclosed systems,no particular arrangement of software for implementing these functionalaspects should be inferred from these descriptions unless explicitlystated or otherwise clear from the context. Similarly, it will beappreciated that the various steps identified and described above may bevaried, and that the order of steps may be adapted to particularapplications of the techniques disclosed herein. All such variations andmodifications are intended to fall within the scope of this disclosure.As such, the depiction and/or description of an order for various stepsshould not be understood to require a particular order of execution forthose steps, unless required by a particular application, or explicitlystated or otherwise clear from the context.

The methods and/or processes described above, and steps thereof, may berealized in hardware, software or any combination of hardware andsoftware suitable for a particular application. The hardware may includea general purpose computer and/or dedicated computing device or specificcomputing device or particular aspect or component of a specificcomputing device. The processes may be realized in one or moremicroprocessors, microcontrollers, embedded microcontrollers,programmable digital signal processors or other programmable device,along with internal and/or external memory. The processes may also, orinstead, be embodied in an application specific integrated circuit, aprogrammable gate array, programmable array logic, or any other deviceor combination of devices that may be configured to process electronicsignals. It will further be appreciated that one or more of theprocesses may be realized as a computer executable code capable of beingexecuted on a machine readable medium.

The computer executable code may be created using a structuredprogramming language such as C, an object oriented programming languagesuch as C++, or any other high-level or low-level programming language(including assembly languages, hardware description languages, anddatabase programming languages and technologies) that may be stored,compiled or interpreted to run on one of the above devices, as well asheterogeneous combinations of processors, processor architectures, orcombinations of different hardware and software, or any other machinecapable of executing program instructions.

Thus, in one aspect, each method described above and combinationsthereof may be embodied in computer executable code that, when executingon one or more computing devices, performs the steps thereof. In anotheraspect, the methods may be embodied in systems that perform the stepsthereof, and may be distributed across devices in a number of ways, orall of the functionality may be integrated into a dedicated, standalonedevice or other hardware. In another aspect, the means for performingthe steps associated with the processes described above may include anyof the hardware and/or software described above. All such permutationsand combinations are intended to fall within the scope of the presentdisclosure.

All documents referenced herein are hereby incorporated by reference.

What is claimed is:
 1. A method for determining state changes of devicesin a building, the method performed by a monitoring device in thebuilding, the method comprising: receiving an electrical signal, whereinthe electrical signal corresponds to electrical usage of a plurality ofdevices, and wherein the electrical signal comprises at least one ofvoltage signal, a current signal, a power signal, or a reactive powersignal; identifying an electrical event in the electrical signal,wherein the electrical event corresponds to a first time; computing afirst feature using a first portion of the electrical signal, whereinthe first portion comprises the first time; computing a second featureusing a second portion of the electrical signal, wherein the secondportion comprises the first time and wherein an end time of the secondportion is later than an end time of the first portion; performing firstprocessing comprising: computing a first score using the first featureand a model, wherein the model corresponds to one or more devices and astate change of the one or more devices and wherein computing the firstscore does not use the second feature, and selecting, using the firstscore, a first device and a first state change; and performing secondprocessing comprising: computing a second score using the first feature,the second feature, and the model, and selecting, using the secondscore, (i) the first device and the first state change, or (ii) a seconddevice and a second state change.
 2. The method of claim 1, whereinidentifying the electrical event in the electrical signal comprisescomputing a first value for a first window of the electrical signalprior to the first time, computing a second value for a second window ofthe electrical signal after the first time, and comparing the firstvalue to the second value.
 3. The method of claim 1, wherein the firstfeature is computed before the end time of the second portion of theelectrical signal.
 4. The method of claim 1, wherein: the firstprocessing further comprises transmitting, to a first server computer,first information about the first device and the first state change; andthe second processing further comprises transmitting, to a second servercomputer, second information about (i) the first device and the firststate change or (ii) the second device and the second state change. 5.The method of claim 1, wherein the first processing further comprisescomputing the first score using a transition model that corresponds to astate change of an element of the first device and a directed graphdescribing a plurality of state changes of the first device.
 6. Themethod of claim 1, wherein the first processing further comprisesselecting the first device and the first state change by generating adirected graph with a plurality of nodes, wherein a first node of thegraph corresponds to the first device and the first state change.
 7. Themethod of claim 4, wherein the first processing further comprisestransmitting the first information to the first server withoutsignificant delay from the first time.
 8. A monitoring device fordetermining state changes of devices in a building, the devicecomprising: at least one processor; at least one memory storingprocessor-executable instructions that, when executed by the at leastone processor, cause the at least one processor to: receive anelectrical signal, wherein the electrical signal corresponds toelectrical usage of a plurality of devices; identify an electrical eventin the electrical signal, wherein the electrical event corresponds to afirst time; compute a first feature using a first portion of theelectrical signal, wherein the first portion comprises the first time;compute a second feature using a second portion of the electricalsignal, wherein the second portion comprises the first time and whereinan end time of the second portion is later than an end time of the firstportion; perform first processing comprising: computing a first scoreusing the first feature, wherein computing the first score does not usethe second feature, and selecting, using the first score, a first deviceand a first state change; and perform second processing comprising:computing a second score using the first feature and the second feature,and selecting, using the second score, (i) the first device and thefirst state change, or (ii) a second device and a second state change.9. The monitoring device of claim 8, wherein the at least one processoridentifies the electrical event in the electrical signal by computing afirst value for a first window of the electrical signal prior to thefirst time, computing a second value for a second window of theelectrical signal after the first time, and comparing the first value tothe second value.
 10. The monitoring device of claim 8, wherein thefirst feature is computed before the end time of the second portion ofthe electrical signal.
 11. The monitoring device of claim 8, wherein:the first processing further comprises transmitting, to a first servercomputer, first information about the first device and the first statechange; and the second processing further comprises transmitting, to asecond server computer, second information about (i) the first deviceand the first state change or (ii) the second device and the secondstate change.
 12. The monitoring device of claim 8, wherein the firstprocessing further comprises computing the first score using atransition model that corresponds to a state change of an element of thefirst device and a directed graph describing a plurality of statechanges of the first device.
 13. The monitoring device of claim 8,wherein the first processing further comprises selecting the firstdevice and the first state change by generating a directed graph with aplurality of nodes, wherein a first node of the graph corresponds to thefirst device and the first state change.
 14. The monitoring device ofclaim 11, wherein the first processing further comprises transmittingthe first information to the first server without significant delay fromthe first time.
 15. A non-transitory computer-readable medium comprisingcomputer executable instructions that, when executed, cause at least oneprocessor to perform actions comprising: receiving an electrical signal,wherein the electrical signal corresponds to electrical usage of aplurality of devices; identifying an electrical event in the electricalsignal, wherein the electrical event corresponds to a first time;computing a first feature using a first portion of the electricalsignal, wherein the first portion comprises the first time; computing asecond feature using a second portion of the electrical signal, whereinthe second portion comprises the first time and wherein an end time ofthe second portion is later than an end time of the first portion;performing first processing comprising: computing a first score usingthe first feature, wherein computing the first score does not use thesecond feature, and selecting, using the first score, a first device anda first state change; and performing second processing comprising:computing a second score using the first feature and the second feature,and selecting, using the second score, (i) the first device and thefirst state change, or (ii) a second device and a second state change.16. The computer-readable medium of claim 15, wherein identifying theelectrical event in the electrical signal comprises computing a firstvalue for a first window of the electrical signal prior to the firsttime, computing a second value for a second window of the electricalsignal after the first time, and comparing the first value to the secondvalue.
 17. The computer-readable medium of claim 15, wherein the firstfeature is computed before the end time of the second portion of theelectrical signal.
 18. The computer-readable medium of claim 15,wherein: the first processing further comprises transmitting, to a firstserver computer, first information about the first device and the firststate change; and the second processing further comprises transmitting,to a second server computer, second information about (i) the firstdevice and the first state change or (ii) the second device and thesecond state change.
 19. The computer-readable medium of claim 15,wherein the first processing further comprises computing the first scoreusing a transition model that corresponds to a state change of anelement of the first device and a directed graph describing a pluralityof state changes of the first device.
 20. The computer-readable mediumof claim 18, wherein the first processing further comprises transmittingthe first information to the first server without significant delay fromthe first time.
 21. The computer-readable medium of claim 18, whereinthe first information is used to provide real-time information about thefirst device to a user and the second information is used to providehistorical information about the first device or the second device tothe user.